摘要
发展高效、高选择性的有机反应和寻找环境友好的合成方法,已经成为有机化学研究的重要内容。对金属催化有机反应的研究日益引起人们的兴趣,其中对金属钯作为高效催化剂的研究最为热门。本论文研究了金属钯催化剂在有机合成中的应用。内容主要集中在两个方面,一是Pd/C催化的化学选择性氢化反应,二是钯试剂催化的水相有机反应。
Pd/C作为一种最传统的钯催化剂,在催化氢化方面有着广泛地应用。论文系统地研究了Pd/C催化氢化还原活性苯甲醛成相应甲苯的方法,首次提出了缩醛反应机理。在酸性条件下以甲醇或乙醇做溶剂催化氢化还原活性苯甲醛时,反应首先是苯甲醛和甲醇或乙醇形成缩醛,然后通过两次碳氧键的氢解得到相应的甲苯。通过简单地在传统的Pd/C催化体系中加入氯仿,即可建立起一个活性自调节的Pd/C催化体系。利用氯仿在Pd/C催化氢化条件下去氯氢化原位产生氯化氢对Pd/C催化剂催化活性的调节,实现了芳香醛的直接还原胺化反应。用该方法能够减少芳香醛直接催化还原胺化过程中的副反应,而且产物以盐酸盐的形成直接从体系中方便地分离出来。最后,还提出了一个新颖的四步催化循环机理。
在论文的第4章中,设计和合成了二醛肟配体并探讨了它在Suzuki反应中的应用。利用该配体,成功地实现了水相中氯苯和溴苯的Suzuki反应,反应只需要0.1 mol%的催化剂。由于该配体能够和钯形成双核的配合物,比普通的醛肟具有更高的催化活性。催化剂具有很高的TON值,在经过4次原位循环反应后,催化剂还能够保持较高的活性。
论文研究了水相条件下不同还原剂在钯催化的卤代芳烃的自身偶联反应中的应用,通过对比发现葡萄糖作为还原剂具有较好的反应效果。同时还发现,使用相转移催化剂可以显著提高反应的产率。该反应可以在无配体的条件下进行,无论溴代苯和溴代杂芳环均能取得较高的产率。
Development of highly efficient and selective reactions was an important part in modern organic chemistry. Catalytic reactions, especially the palladium catalyzed reactions, most attracted our attention. In this thesis, the application of palladium catalysts in organic synthesis were studies mainly focusing on two aspects. One is the chemical selectivity of the Pd/C catalyst in catalytic hydrogenations, the other is the application of palladium catalyst in aqueous reaction.
As a traditional palladium catalyst, Pd/C was widely used in catalytic hydrogenation. In chapter 2, the catalytic hydrogenolysis of benzaldehydes to methylbenzenes was studied. A three stage novel‘acetal pathway’was first revealed by a systematic study when lower alcohols were used as solvents. In the first stage, benzaldehyde carried out an acetalization catalyzed by aq. HCl and Pd/C together to yield dimethyl acetal. Then, dimethyl acetal carried out a Pd/C catalyzed“fast hydrogenolysis”to give the benzyl methyl ether. Finally, benzyl methyl ether underwent a Pd-C catalyzed“slow hydrogenolysis”to give methylbenzene. A solvent-controlled highly efficient procedure for hydrogenolysis of benzaldehydes to methylbenzenes was established.
In chapter 3, by adding a few milliliters of CHCl3 in the conventional Pd/C catalytic hydrogenation condition, a self-adjusted system was established. Using this system, an unprecedented efficient and chemoselective DRA of benzaldehydes and primary amines was developed to directly yield N-substituted benzylamine hydrochlorides as single products in practically quantitative yields. A four-stage cyclic pathway was proposed.
In chapter 4, a group of dioxime ligands were designed and synthesized. The ligands may form dinuclear complexes with palladium, by that a novel aqueous Suzuki coupling between halobenenzes and phenylboronic acids was catalyzed efficiently. The catalyst had a very high TON with very low loading (0.1 mol%) and can be recycled four times in suit without significant lose of the reactivity.
In chapter 5, the aqueous homocoupling of bromoarenes was studied systematically by using different reducing agents. As a result, we found that glucose is the most efficient reducing agent and the phase transfer catalyst played a very important role in the coupling reaction. When phase transfer catalyst was used, the yield of the homocoupling was improved. The homocoupling reaction was carried out using palladium diacetate as catalyst without any ligand. Both bromopyridines and bromobenzenes can give good results.
引文
[1] Blaser H U, Indolese A, Schnyder A, et al. Supported palladium catalysts for fine chemicals synthesis. Journal of Molecular Catalysis A: Chemical, 2001, 173: 3-18.
[2]姜麟忠.催化氢化在有机合成中的应用.北京:化学工业出版社, 1987: 1-12.
[3] Bornstein J, Bedell S F, Drummond P E, et al. The synthesis ofα-amino-o-tolualdehyde diethylacetal and its attempted conversion to pseudoisoindole. J. Am. Chem. Soc., 2005, 127: 4596-4598.
[4] Luesch H, Hoffman D, Level J, et al. Biosynthesis of 4-methylproline in cyanobacteria: cloning of nosE and nosF genes and biochemical characterization of the encoded dehydrogenase and reductase activities. J. Org. Chem., 2003, 68: 83-91.
[5] Souweha M S, Enright G D, Fallis A G, et al. Vinigrol: A compact, Diene-Transmissive Diels-Alder strategy to the tricyclic core. Org. Lett., 2007, 9: 5163-5166.
[6] Sajiki H, Hirota K. A novel type of Pd/C-catalyzed hydrogenation using a catalyst poison: chemoselective inhibition of the hydrogenolysis of O-benzyl protective groups by the addition of a nitrogen-containing base. Tetrahedron, 1998, 54: 13981-13986.
[7] Sajiki H, Kuno H, Hirota K. Suppression effect of the Pd/C-catalyzed hydrogenolysis of a phenolic benzyl protective group by the addition of nitrogen-containing bases. Tetrahedron Lett., 1998, 39: 7127-7130.
[8] Sajiki H, Kuno H, Hirota K. The formation of a novel Pd/C-ethylenediamine complex catalyst: chemoselective hydrogenation without deprotection of the O-Benzyl and N-cbz groups. J. Org. Chem., 1998, 63: 7990-7992.
[9] Sajiki H, Kuno H, Hirota K. Easy and partial hydrogenation of aromatic carbonyls to benzyl alcohols using Pd/C(ethylenediamine)-catalyst. J. Chem. Soc., Perkin Trans. 1: Org. and Bio-Org. Chem., 1998, 24: 4043-4044.
[10] Cheng C J, Wang X Y, Xing L X, et al. An efficient and practical method for highly chemoselective hydrogenation of nitrobenzylamines to aminobenzylamine hydrochlorides. Adv. Synth. Catal., 2007, 349: 1775-1780.
[11] Takaya H, Mashima K, Koyano K, et al. Practical synthesis of (R)- or (S)-2,2'-bis(diarylp- hosphino)-1,1'-binaphthyls (BINAPs). J. Org. Chem., 1986, 51: 629-635.
[12] Ogasawara M, Ueyama K, Nagano T, et al. Palladium-catalyzed asymmetric synthesis of axially chiral (allenylmethyl)silanes and chirality transfer to stereogenic carbon centers in SE' reactions. Org. Lett., 2003, 5: 217-219.
[13] Benincori T, Cesarotti E, Piccolo O, et al. 2,2',5,5'-Tetramethyl-4,4'-bis(diphenylphoshino)-3,3'-bithiophene: A new, very efficient, easily accessible, chiral biheteroaromatic ligand for homogeneous stereoselective Catalysis. J. Org. Chem., 2000, 65: 2043-2047.
[14] Knierzinger A, Schoenholze P. Axially dissymmetric diphosphines in the biphenyl series: crystal structures of three new Group VIII metal complexes of (6,6'-dimethyl-1,1'-biphenyl -2,2'-diyl)bis(diphenylphosphine)(biphemp). Helv. Chim. Acta, 1992, 75: 1211-1120.
[15] Wang Y, Zhou Y. Highly enantioselective Pd-catalyzed asymmetric hydrogenation of N-diphenylphosphinyl ketimines. Synlett, 2006, 8: 1189-1192.
[16] Wang Y, Lu S, Zhou Y. Highly enantioselective Pd-catalyzed asymmetric hydrogenation of activated imines. J. Org. Chem., 2007, 72: 3739-3734.
[17] Hu A, Ogasawara M, Sakamoto T. Palladium-catalyzed intermolecular asymmetric hydroamination with 4,4'-disubstituted BINAP and SEGPHOS. Adv. Synth. Catal., 2006, 348: 2051-2056.
[18] Dieguez M, Pamies O, Claver C. Palladium-diphosphite catalysts for the asymmetric allylic substitution reactions. J. Org. Chem., 2005, 70: 3363-3368.
[19] Faller J W, Wilt J C. Palladium/BINAP(S)-catalyzed asymmetric allylic amination. Org. Lett., 2005, 7: 633-636.
[20] Maitro G, Vogel S, Sadaoui M. Enantioselective synthesis of aryl sulfoxides via palladium catalyzed arylation of sulfenate anions. Org. Lett., 2007, 9: 5493-5496.
[21] Li K, Hii K K. Dicationic [(BINAP)Pd(solvent)2]2+[TfO?]2: enantioselective hydroamination catalyst for alkenoyl-N-oxazolidinones. Chem. Commun., 2003, 1132-1133.
[22] Xie J, Duan H, Fan B. Application of SDP ligands for Pd-catalysed allylic alkylation. Adv. Synth. Catal., 2004, 346: 625-632.
[23] Chen X, Guo R, Li Y. Application of phosphinous amide ligands in palladium complex catalyzed asymmetric allylic alkylation: influence of steric effects on enantioselectivity. Tetrahedron: Asymmetry, 2004, 15: 213-217.
[24] Hu X, Chen H, Dai H, Synthesis of novel P-ketimine bidentate ferrocenyl ligands with central and planar chirality and comparison in the catalytic activity between P-ketimine and P-aldimine. Tetrahedron: Asymmetry, 2003, 14: 3415-3421.
[25] Tietze L F, Lohmann J K, Stadler C. Synthesis of novel highly active thiophene and benzothiophene containing diphosphine ligands and their use in the asymmetric allylation of catechol. Synlett, 2004, 1113-1116.
[26] Remmele H, Kollhofer A, Plenio H. Recyclable catalyst with cationic phase tags for the Sonogashira coupling of aryl bromides and aryl chlorides. Organometallics, 2003, 22: 4098-4103.
[27] Cossy J, de Filippis A, Pardo D G, et al. Palladium-catalyzed intermolecularα-arylation of N-protected 2-piperinones. Org. Lett., 2003, 5: 3037-3039.
[28] Willis M C, Brace G N, Findlay T J K. 2-(2-Haloalkenyl)-aryl halides as substrates for palladium-catalysed tandem C-N bond formation: efficient synthesis of 1-substituted indoles. Adv. Synth. Catal., 2006, 348: 851-856.
[29] Fihri A, Jierso J C, Vion A. Diphosphines of dppf-type incorporating electron withdrawing furyl moieties substantially improve the palladium-catalysed amination of allyl acetates. Adv. Synth. Catal., 2005, 347: 1198-1202.
[30] Kataoka N, Shelby Q, Stambuli J P. Air-stable, sterically hindered ferrocenyl dialkylphosp- hines for palladium-catalyzed C-C, C-N, and C-O bond-forming cross-couplings. J. Org. Chem., 2002, 67: 5553-5566.
[31] Fischer E O, Maasbo1 A. On the existence of a Tungsten carbonyl cabrene complex. Angew. Chem. Int. Ed. Engl., 1964, 3: 580-581.
[32] Ofele K l. 1,3-Dimethyl-4-Imidazolinyliden-(2)-pentacbaronylchromein neuer ubergangs- metall carben komplex. J. Organomet. Chem., 1968, 12: 42-43.
[33] Wanzlick H W, Schonherr H J. Direct synthesis of a Mercury salt-carbene complex. Angew. Chem. Int. Ed. Engl., 1968, 7: 141-142.
[34] Arduengo A J, Harlow R L, Kline M, Satble cyrsatlline carbine. J. Am. Chem. Soc., 1991 113: 361-363.
[35] Li C J, Chan T. Organometallic reactions in aqueous media 2. Convenient synthesis of methylenetetrahydrofurans. Organometallics, 1991, 10; 2548-2549.
[36] Chung W J, Seiichiro H, Welch J T. The indium-mediated Reformatski reactions of 2,2-difluoro-2-halo-1-furan-2-ylethanones in aqueous media. J. Fluorine Chem., 2001, 112: 343-347.
[37] Shen Z, Yeo Y L, Loh T P. et al Indium-copper and indium-silver mediated Barbier-Grignard type alkylation reaction of aldehydes using unactivated alkyl halides in water. J. Org. Chem., 2008, 73: 3922-3924.
[38] Mizoraki T, Mori K, Ozaki A. Arylation of the olefin with aryl iodile catalyzed by palladium. Bull. Chem. Soc. Jpn., 1971, 44: 581
[39] Heck R F, Nolley J P. Palladium-catalyzed vinylic hydron substitution reactions with aryl, benzyl, and styryl halides. J. Org. Chem., 1972, 37: 2320-2322.
[40] Jeffery T. Heck-type reaction in water. Tetrahedron Lett., 1994, 35: 3051-3054.
[41] Solabannavar S B, Desai U V, Mane R B. Heck reaction in aqueous medium using Amberlite IRA-400 (basic). Green Chemistry, 2002, 4: 347-348.
[42] Hagiwara H, Sugawara Y, Hoshi T. Sustainable Mizoroki–Heck reaction in water: remarkably high activity of Pd(OAc)2 immobilized on reversed phase silica gel with the aid of an ionic liquid. Chem. Commun., 2005, 2042-2044.
[43] Najera C, Karlstroem S, Falvello L R, et al. Di-2-pyridylmethylamine-based palladiumcomplexes as new catalysts for Heck, Suzuki, and Sonogashira reactions in organic and aqueous Solvents. Org. Lett., 2003, 5: 1451-1454.
[44] Zhang Z, Zha Z, Gan C, et al. Catalysis and regioselectivity of the aqueous Heck reaction by Pd(0) nanoparticles under ultrasonic irradiation. J. Org. Chem., 2006, 71: 4339-4342.
[45] Dieck H A, Heck F R. Palladium catalyzed synthesis of aryl, heterocyclic, and vinylic acetylene derivatives. J. Organomet. Chem., 1975, 93: 259-263.
[46] Cassar L. Synthesis of aryl- and vinyl-substituted acetylene derivatives by the use of nickel and palladium complexes. J. Organomet. Chem., 1975, 93: 253-537.
[47] Sonogashira K, Tohda Y, Hagihara N. Convenient synthesis of acetylenes. Catalytic substitutions of acetylenic hydrogen with bromo alkenes, iodo arenes, and bromopyridines. Tetrahedron Lett., 1975, 50: 4467-70.
[48] Rossi R, Carpita A, Quirici M G, et al. Insect sex pheromones: Palladium-catalyzed synthesis of aliohatic 1,3-enynes by reaction of 1-alhynes with alkenyl halides under phase transfer conditions. Tetrahedron, 1982 38: 631-637.
[49] Santanu B, Saumitra S. Palladium-catalyzed alkynylation of aryl halides (Sonogashira reaction) in water. Tetrahedron lett., 2004, 45: 8733-8736.
[51] Miyaua N, Yamada K, Suzuki A. A new stereospecific cross-couping by the palladium catalyzed reaction of 1-alkenylboranes with 1-alkenyl or 1-alkynyl halides. Tetrahedron, 1979, 36: 3437-3440.
[52] Miyaua N, Suzuki A. Stereoselective synthesis of arylated (E)-alkenes by the reaction of alk-1-enyloranes with aryl halides in the presence of palladium catalyst. J. Chem. Soc. Chem. Commun., 1979, 866-867.
[50] Liang B, Huang M, You Z, et al. Pd-catalyzed copper-free carbonylative sonogashira reaction of aryl iodides with alkynes for synthesis of alkynyl ketones and flavones by using water as solvent. J. Org. Chem., 2005, 70: 6097-6100.
[53] Bumagin N A, Bykov V. Ligandless Palladium catalyzed reactions of arylboronic acids and sodium tetraphenylborate with aryl halides in aqueous media. Tetrahedron, 1997, 53: 14437-14450.
[55] Uozumi Y Y, Danjo H, Hayashi T. Cross-coupling of aryl halides and allyl acetates with arylboron reagents in water using an amphiphilic resin-supported palladium catalyst. J. Org. Chem., 1999, 64:3384-3388.
[56] Uozumi Y, Nakai Y. An Amphiphilic resin-supported palladium catalyst for high- throughput cross-coupling in water. Org. Lett., 2000, 4: 2997-3000.
[57] Ryu J, Jang C, Yoo Y, et al. Supramolecular reactor in an aqueous environment: aromatic cross Suzuki coupling reaction at room temperature. J. Org. Chem., 2005, 70: 8956-8962.
[58] Baleizao C, Corma A, Garcia H, et al. Oxime carbapalladacycle covalently anchored to highsurface area inorganic supports or polymers as heterogeneous green catalysts for the Suzuki reaction in water. J. Org. Chem., 2004, 69: 439-446.
[59] Wu W, Chen S, Tsai F. Recyclable and highly active cationic 2,2-bipyridyl palladium(II) catalyst for Suzuki cross-coupling reaction in water. Tetrahedron Lett., 2006, 47: 9267-9230
[60] Ines B, SanMartin R, Churruca F, et al. A nonsymmetric pincer-type palladium catalyst in Suzuki, Sonogashira, and Hiyama couplings in neat water. Organometallics, 2008, 27: 2833-2839.
[61] Nishimura S. Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis, John Wiley & Sons: New York, NY, 2001; Chapter 5
[62] Rylander P N. Hydrogenation Methods, Academic: London, 1985; Chapter 4.
[63] Merz A, Rauschel M. Synthesis of crown ethers related to ubiquinones. Synthesis, 1993, 797-802.
[64] Benacides A, Peralta J, Delgado F, et al. Total ssynthesis of the natural carbazoles Murrayanine and Murrayafoline A, Based on the regioselective Diels–Alder addition of exo-2-oxazolidinone dienes. Synthesis, 2004, 2499-2504.
[65] Sagar K S, Chang C, Wang W, et al. Preparation and anti-HIV activities of retrojusticidin B analogs and azalignans. Bioorg. Med. Chem., 2004, 12: 4045-4054.
[66] Chida N, Ohtsuka M, Nakazawa K, et al. Total synthesis of antibiotic hygromycin A. J. Org. Chem., 1991, 56: 2976-2983.
[67] Wang Q, Yang Y, Li Y, et al. An efficient method for the synthesis of lignans, Tetrahedron, 2006, 62, 6107-6112.
[68] Connolly T J, Matchett M, Sukhtankar S, et al. A practical synthesis of 3,4-dimethoxy-o -toluic acid. Org. Process Res. Dev., 2004, 8: 624-627.
[69] Anderson W K, Boehm T L, Makara G M, et al. Synthesis and modeling studies with monocyclic analogues of Mycophenolic Acid. J. Med. Chem., 1996, 39: 46-55.
[70] Monte A P, Marona-Lewicka D, Parker M A et al. Dihydrobenzofuran analogues of hallucinogens. 3. Models of 4-substituted (2,5-dimethoxyphenyl)alkylamine derivatives with rigidified methoxy groups. J. Med. Chem., 1996, 39: 2953-2961.
[71] Sype L, Kloc K, Mlochowski J. Synthesis of ubiquinone and menaquinone analogs by oxidative demethylation of alkenylhydroquinone ethers with argentic oxide or ceric ammonium nitrate in the presence of 2,4,6-pyridinetricarboxylic acid. Tetrahedron, 1980, 36: 123-129.
[72] Boyer F D, Ducrot P H, Hydrogenation of substituted aromatic aldehydes: nucleophilic trapping of the reaction intermediate, application to the efficient synthesis of methylene linked flavanol dimmers. Tetrahedron Lett., 2005, 46: 5177-5180
[73] Yamaguchi S, Muro S, Kobayashi M, et al. Absolute structures of some naturally occurringisopropenyldihydrobenzofurans, remirol, remiridiol, angenomalin, and isoangenomalin. J. Org. Chem., 2003, 68: 6274-6278.
[74] Lai C, Shen Y, Wang M, et al. Intermolecular Diels-Alder reactions of brominated masked o-benzoquinones with electron-deficient dienophiles. A detour method to synthesize bicycle [2.2.2]octenones from 2-methoxyphenols. J. Org. Chem., 2002, 67: 6493-6502.
[75] Clive D L J, Tao Y, Bo Y, et al. Synthetic studies on calicheamicinγ1I-synthesis of (–)-calicheamicinone and models representing the four sugars and the aromatic system. Chem. Commun., 2000, 1341-1350.
[76] de Paulis T, Kumar Y, Johansson L, et al. Potential neuroleptic agents. 4. Chemistry, behavioral pharmacology, and inhibition of [3H]spiperone binding of 3,5-disubstituted N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-methoxysalicylamides. J. Med. Chem., 1986, 29: 61-69.
[77] Wenkert E, Loeser E M, Mahapatra S N, et al. Wheat bran phenols. J. Org. Chem., 1964, 29, 435-439.
[78] Lipshutz B H, Lower A, Berl V, et al. An improved synthesis of the "Miracle Nutrient" coenzyme Q10. Org. Lett., 2005, 7: 4095-4097.
[79] Min J H, Lee J S, Yang J D, et al. The Friedel-Crafts allylation of a prenyl group stabilized by a sulfone moiety: Expeditious syntheses of ubiquinones and menaquinones. J. Org. Chem., 2003, 68: 7925-7927.
[80] Negishi E I, Liou S Y, Xu C, et al. A novel, highly delective, and general methodology for the dynthesis of 1,5-diene-containing oligoisoprenoids of all possible geometrical combinations exemplified by aniterative and convergent synthesis of coenzyme Q10. Org. Lett. 2002, 4: 261-264.
[81] Lipshutz B H, Mollard P, Pfeiffer S S, et al. A short, highly efficient synthesis of coenzyme Q10. J. Am. Chem. Soc., 2002, 124: 14282-14283
[82] Lipshutz B H, Bulow G, Fernandez-Lazaro F, et al. A convergent approach to coenzyme Q. J. Am. Chem. Soc, 1999, 121: 11664-11673.
[83] Lipshutz B H, Bulow G, Lowe R F, et al. A novel route to coenzyme Q0. J. Am. Chem. Soc., 1996, 118: 5512-5513.
[84] Carpino L A, Triolo S A, Berglund R A. Reductive lactonization of strategically methylated quinone propionic acid esters and amides. J. Org. Chem., 1989, 54: 3303-3310.
[85] Keinan E, Eren D. Total synthesis of linear polyprenoids. 2. Improved preparation of the aromatic nucleus of ubiquinone. J. Org. Chem., 1987, 52: 3872-3875.
[86] Terao S, Kato K, Shiraishi M, et al. Synthesis of ubiquinones. 2. An efficient preparation of ubiquinone-10. J. Org. Chem., 1979, 44: 868-869.
[87] Ji Y, Xu W, Jin W, et al. Practical Synthesis of 2,3,4,5-Tetramethoxytoluene. Synth.Commun., 2006, 36: 1961-1965.
[88] Lu L, Chen F. A novel and convenient synthesis of coenzyme Q1. Synth. Commun., 2004, 34: 4049-4053.
[89] Chida A S, Vani P V, Chandrasekharam M, et al. Synthesis of 2,3-dimethoxy-5-methyl- 1,4-benzoquinone: a key fragment in coenzyme-Q. Synth. Commun., 2001, 31: 657-660.
[90]程传杰,宋华付,陈玉岩,等.微波辐射法合成辅酶Q-0合成化学, 2004, 12: 319-322.
[91] Iwamura T, Kihara Y, Hattori K. Process for producing methyl-substituted aromatic compound PCT Int. Appl. WO 2003095399, 2003
[92] Bottke N, Fischer R, Noebel T, et al. Hydrogenolysis process and catalysts for producing 3,4,5-trisubstituted toluene derivatives from their corresponding benzyl alcohols or benzaldehydes PCT Int. Appl. WO 2003062174, 2003
[93] Fujii Y, Furugaki H, Tamura S. A convenient catalytic method for the synthesis of ethers from alcohols and carbonyl compounds, Bull. Chem. Soc. Jpn., 2005, 78: 456-463.
[94] Bethmont V, Fache F, Lemaire M, An alternative catalytic method to the Williamson's synthesis of ethers. Tetrahedron Lett., 1995, 36: 4235-4236.
[95] Adsms R, Cain C K, Wollf H, Structure of cannabidiol. II. Absorption spectra compared with those of various dihydric phenols. J. Am. Chem. Soc., 1940, 62: 732-734.
[96] Smith W B, Deavenport D L, Ihrig A M. Substituent effects of aromatic proton chemical shifts. VIII. Conformational effects of the carbonyl group in benzenes and naphthalenes. J. Am. Chem. Soc., 1972, 94, 1959-1961.
[97] Borch R F, Bernstein M D, Durst H D. Cyanohydridoborate anion as a selective reducing agent. J. Am. Chem.Soc., 1971, 93: 2897-2904.
[98] Zhang J, Blazecka P G, Davidson J G. First direct reductive amination of mucochloric acid: A simple and efficient method for preparing highly functionalized ,β-unsaturated -butyrolactams. Org. Lett., 2003, 5: 553-556.
[99] Shibata I, Moriuchi-Kawakami T, Tanizawa D, et al. Chemoselective reductions of imino groups by dibutyltin chloride hydride complex. J. Org. Chem., 1998, 63: 383-385.
[100] Bomann M D, Guch I C, DiMare M, A mild, pyridine-borane-based reductive amination protocol. J. Org. Chem., 1995, 60, 5995-5996.
[101] Bhattacharyya S. Reductive alkylation of dimethylamine using titanium(IV) isopropoxide and sodium borohydride: an efficient, safe, and convenient method for the synthesis of N,N-dimethylated tertiary amines. J. Org. Chem., 1995, 60: 4928-4929.
[102] Ranu B C, Majee A, Sarkar A. 1. One-pot reductive amination of conjugated aldehydes and ketones with Silica Gel and zinc borohydride. J. Org. Chem,. 1998, 63: 370-373.
[103] Suwa T, Sugiyama E, Shibata I, et al. Selective alpha-stannylated addition ofdi-n-butyliodotin hydride Ate complex to simple aliphatic alkynes. Synlett, 2000, 556-558.
[104] Suwa T, Shibata I, Nishino K, et al. Synthesis of nitrogen heterocycles by intramolecular michael type of amination via reduction of imines with di-n-butyliodotin hydride (n-Bu2SnIH). Org. Lett., 1999, 1: 1579-1581.
[105] Nishimura S. Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis. John Wiley & Sons, Inc.: New York, 2001, pp: 236-241.
[106] Frutos R P, Gallou I, Reeves D, et al. Expedient synthesis of substituted imidazoles from nitriles. Tetrahedron Lett., 2005, 46: 8369-8372.
[107] Botta M, Corelli F, Gasparrini F, et al. Chiral azole derivatives. 4. enantiomers of bifonazole and related antifungal agents: Synthesis, Configuration Assignment, and Biological Evaluation. J. Org. Chem., 2000, 65, 4736-4739.
[108] Wang T, Cloudsdale I S. synthesis of 1,4-dialkyl-1,4-dihydro-1,4-benzo[e]diazepin-5- ones. Synthesis, 2000, 265-268.
[109] Guarna A, Guidi A, Machetti F, et al. Synthesis and reactivity of bicycles derived from tartaric acid and -amino acids: A novel class of conformationally constrained dipeptide isosteres based upon enantiopure 3-aza-6,8-dioxabicyclo[3.2.1]octane-7- carboxylic acid. J. Org. Chem., 1999, 64: 7347-7364.
[110] Campbell A D, Raynham T M, Taylor R J K. The total synthesis of (–)-α-kainic acid using titanium-mediated diene metallabicyclisation methodology, Chem. Commun., 1999, 245-246.
[111] Zimmerman S C, Duerr B F, Controlled molecular aggregation. 1. Cyclic trimerization via hydrogen bonding. J. Org. Chem., 1992, 57: 2215-2217.
[112] Kruse L I, Kaiser C, DeWolf W E, et al. Some benzyl-substituted imidazoles, triazoles, tetrazoles, pyridinethiones, and structural relatives as multisubstrate inhibitors of dopamine .beta.-hydroxylase. 4. Structure-activity relationships at the copper binding site. J. Med. Chem., 1990, 33, 781-789.
[113] Ross S T, Kruse L I, Ohlstein E H, et al. Inhibitors of dopamine .beta.-hydroxylase. 3. Some 1-(pyridylmethyl)imidazole-2-thiones. J. Med. Chem., 1987, 30: 1309-1313.
[114] Chien T C, Meade E A, Hinkley J M, et al. Facile synthesis of 1-substituted 2-amino-3 -cyanopyrroles: New synthetic precursors for 5,6-unsubstituted pyrrolo[2,3-d]pyrimidines. Org. Lett., 2004, 6: 2857-2859.
[115] Rosenstrom U, Skold C, Lindeberg G, et al. A Selective AT2 receptor ligand with a -turn-like mimetic replacing the amino acid residues 4-5 of angiotensin II. J. Med. Chem., 2004, 47: 859-870.
[116] Diaz-Gavilan M, Rodriguez-Serrano F, Gomez-Vidal J A. Synthesis of tetrahydroben -zoxazepine acetals with electron-withdrawing groups on the nitrogen atom. Novel scaffolds endowed with anticancer activity against breast cancer cells, Tetrahedron, 2004, 60: 11547-11557.
[117] Chan C, Heid R, Zheng S, et al. Total synthesis of cribrostatin IV: Fine-tuning the character of an amide bond by remote control. J. Am. Chem. Soc., 2005, 127: 4596-4598.
[118] Zhou B, Guo J, Danishefsky S J. Studies directed to the total synthesis of ET 743 and analogues thereof: an expeditious route to the ABFGH subunit. Org. Lett., 2002, 4: 43-46.
[119] Scott J D, Williams R M. Total Synthesis of (-)-tetrazomine. determination of the tereochemistry of tetrazomine and the synthesis and biological activity of tetrazomine analogues. J. Am. Chem. Soc., 2002, 124: 2951-2956.
[120] Doshi H, Cardis A B, Crelling J K et al. Hofmann degradation of .beta.-hydroxy ammonium salts. II. 4-Hydroxybenzylisoquinoles and 4-hydroxyaporphines. J. Org. Chem., 1987, 52: 2604-2608.
[121] Bobbitt J M. Kulkarni C L, Dutta C P, et al. Syntheses of indoles and carbolines via aminoacetaldehyde acetals. J. Org. Chem., 1978, 43: 3541-3544.
[122] Moreau A, Couture A, Deniau E, et al. A new synthesis of the phytotoxin porritoxin. Tetrahedron, 2006, 62: 5787-5790.
[123] Chrzanowska M, Dreas A, Rozwadowska M D. Synthesis of (S)-(?)- and (R)-(+)-O- methylbharatamine using a diastereoselective Pomeranz–Fritsch–Bobbitt methodology. Tetrahedron: Asymmetry, 2005, 16: 2954-2958.
[124] Ioanoviciu A, Antony S, Pommier Y, et al. Synthesis and mechanism of action studies of a series of norindenoisoquinoline topoisomerase I Poisons reveal an inhibitor with a flipped orientation in the ternary DNA-Enzyme-Inhibitor complex as determined by X-ray crystallographic analysis. J. Med. Chem., 2005, 48: 4803-4814.
[125] G?uszyńska A, Rozwadowska M D. Enantioselective addition of methyllithium to a prochiral imine-the substrate in the Pomeranz-Fritsch-Bobbitt synthesis of tetrahydroisoquinoline derivatives mediated by chiral monooxazolines. Tetrahedron: Asymmetry, 2004, 15: 3289-3295.
[126] Larghi E L, Kaufman T S, Preparation of N-benzylsulfonamido-1,2-dihydroisoquinolines and their reaction with Raney nickel. A mild, new synthesis of isoquinolines. Tetrahedron Lett., 1997, 38: 3159-3162.
[127] Shirasaka T, Takuma Y, Shimpuku T, et al. Practical synthesis of 5,6,7,8-tetrahydro- 4-methoxy-6-methyl-1,3-dioxolo[4,5-g]isoquinolin-5-ol (cotarnine). J. Org. Chem., 1990, 55: 3767-3771.
[128] Kruse L I, Kaiser C, DeWolf W E, et al. Multisubstrate inhibitors of dopamine beta. -hydroxylase. 1. Some 1-phenyl and 1-phenyl-bridged derivatives of imidazole-2-thione. J. Med. Chem., 1986, 29: 2465-2472.
[129] Mitscher L A, Gill H, Filippi J A, et al. Total chemical synthesis and antitumor evaluation of the 9-aza analog of N-(trifluoroacetyl)-4-demethoxydaunomycin. J. Med. Chem., 1986, 29: 1277-1281.
[130] Bates H A, Garelick J S, Synthesis of tetrahydro-4,6,7-isoquinolinetriols and tetrahydro -4,7,8-isoquinolinetriols. J. Org. Chem., 1984, 49: 4552-4555.
[131] Robichaud A, Ajjou A N. First example of direct reductive amination of aldehydes with primary and secondary amines catalyzed by water-soluble transition metal catalysts. Tetrahedron Lett., 2006, 47: 3633-3636.
[132] Imao D, Fujihara S, Yamamoto T, et al. Enantioselective addition of methyllithium to a prochiral imine-the substrate in the Pomeranz-Fritsch-Bobbitt synthesis of tetrahydr -oisoquinoline derivatives mediated by chiral monooxazolines, Tetrahedron, 2005, 61: 6988-6992.
[133] Cheng C J, Wang X Y, Xing L X, et al. An efficient and practical method for highly chemoselective hydrogenation of nitrobenzylamines to aminobenzylamine hydrochlorides. Adv. Synth. Catal., 2007, 349: 1775-1780.
[134] Kaye I A, Minsky I. New Compounds. Preparation of N-substituted aminoacetals. J. Am. Chem. Soc., 1949, 71: 2272-2273.
[135] Meindl W R, Von Angerer E, Schoenenberger H, et al. Benzylamines: Synthesis and evaluation of antimycobacterial properties. J. Med. Chem., 1984, 27: 1111-1118.
[136] Fuller R W, Molloy B B, Day W A, et al. Inhibition of phenylethanolamine N-methyl transferase by benzylamines. 1. Structure-activity relations. J. Med. Chem., 1973, 16: 101- 106.
[137] Lutz R E, Bailey P S, Rowlett R J, et al. Antimalarials: some new secondary and tertiary arylmethylamines. J. Org. Chem., 1947, 12: 760-766.
[138] Gardner J H, Stevens J R. Some heterocyclic derivatives of ethylenediamine. J. Am. Chem. Soc., 1949, 71: 1868-1870.
[139] Flechenstein C A, Plenio H. Highly efficient Suzuki-Miyaura coupling of heterocyclic substrates through rational reaction design. Chem. Eur. J., 2008, 14: 4267-4279.
[140] Bai L, Wang J X. Environmentally friendly Suzuki aryl-aryl cross-coupling reaction. Curr. Org. Chem., 2005, 9: 535-553.
[141] Bellina F, Carpita A, Rossi R. Palladium catalysts for the Suzuki cross-coupling reaction: An overview of recent advances. Synthesis, 2004, 15: 2419-2440.
[142] Kotha S, Lahiri K, Kashinath D. Recent applications of the Suzuki-Miyaura cross-coupling reaction in organic synthesis. Tetrahedron, 2002, 58: 9633-9695.
[143] Chemler S R, Trauner D, Danishefsky S J. The B-alkyl Suzuki-Miyaura cross-couplingreaction: Development, mechanistic study, and applications in natural product synthesis. Angew. Chem. Int. Ed. Engl., 2001, 40: 4544-4568.
[144] Miraura N, Suzuki A. Palladium-catalyzed cross-coupling reactions of organoboron compounds. Chem. Rev., 1995, 95: 2457-2483.
[145] Smith G B, Dezeny G C, Hughes D L. Mechanistic studies of the suzuki cross-coupling reaction. J. Org. Chem., 1994, 59: 8151-8154.
[146] Ennis D S, McManus J, Wood-Kaczmar W. Multikilogram-scale synthesis of a biphenyl carboxylic acid derivative using a Pd/C-mediated Suzuki coupling approach Org. Process Res. Dev., 1999, 3: 248-252.
[147] Jacks T E, Belmont D T, Briggs C A. Development of a scalable process for CI-1034, an endothelin antagonist. Org. Process Res. Dev., 2004, 8: 201-212.
[148] Rowlands G J, Ambifunctional cooperative catalysts. Tetrahedron, 2001, 57: 1865-1882
[149] van den Beuken, E K, Feringa B L. Bimetallic catalysis by late transition metal complexes. Tetrahedron Lett., 1998, 54: 12985-13011.
[150] Steinhagen H, Helmchen G. Asymmetric two-center catalysis-learning from nature. Angew. Chem., Int. Ed. Engl., 1996, 35: 2339-2342.
[151] Bullock R M, Casey C P. Heterobimetallic compounds linked by heterodifunctional ligands. Acc. Chem. Res., 1987, 20: 167-173.
[152] Trost B M; Silcoff E R, Ito H. Direct asymmetric aldol reactions of acetone using bimetallic zinc catalysts. Org. Lett., 2001, 3: 2497-500.
[153] Tsukada N, Tamura O, Inoue Y. Selective cis-addition of C-H bonds of pyrroles and hiophenes to alkynes catalyzed by a dinuclear palladium complex. Tetrahedron Lett., 2005, 46, 7515-7517.
[154] Stockland R A J, Anderson G K, Rath N P. Synthesis and structures of hydride- bridged palladium A-frame complexes. Inorg. Chim. Acta, 2000, 300-302:395-405.
[155] Stockland R A J, Anderson G K, Rath N P. Reductive elimination of alkanes and arenes from [Pd2R2( -H)( -dppm)2]PF6 complexes. J. Am. Chem. Soc., 1999, 121, 7945-7946.
[156] Stockland R A J, Anderson G K, Rath N P. Reactions of [PdX2(dppm)] complexes with Grignard reagents. Organometallics, 1997, 16: 5096-5101.
[157] Stockland R A J, Anderson G K, Rath N P. Synthesis and structures of hydride-bridged palladium A-frame complexes. Inorg. Chim. Acta, 1997, 259: 173-182.
[158] Besenyei G, Parkanyi L, Foch I, et al. Insertion of arylsulfonylnitrene fragments into Pd-Pd bonds. Crystallographic characterization of the novel [Pd2Cl2(μ-dppm)2(μ-NSO2 C6H4NO2-2)] A-frame adduct. Chem. Commun., 1997, 1143-1145.
[159] Besenyei G, Parkanyi L, Foch I, et al. Synthesis and characterization of dinuclear palladium complexes with bridging selenide or selenoxide ligands, including X-ray characterization ofanti-Pd2Cl2(.mu.-Se)(.mu.-dpmMe)2 [dpmMe = 1,1-bis(diphenylphos- phino)ethane]. Inorg. Chem., 1995, 34: 6118-6123.
[160] Davies J A, Kirschbaum K, Kluwe C. Reactions of dimeric palladium(I) complexes with sulfur-substituted acetylenes: 1,2-Heteroatomic shift reactions versus adduct formation. X-ray crystal structures of [Pd2Cl2(.mu.-dppm)2(.mu.-CH3SCCSCH3)].cntdot. CH2Cl2, [Pd2Cl2(.mu.-dmpm)2(.mu.-CH3SCCSCH3)], and [Pd2Cl2(.mu.-dppm)2(.mu.-.sigma.-C:C (CH3)(SCH3))]. Organometallics, 1994, 13: 3664-3670.
[161] Dervisi A, Edwards P G, Newman P D, et al. Palladium diphenyl-2-pyridylphosphine complexes. J. Chem. Soc., Dalton Trans., 1998, 3771-3776.
[162] Reid S M, Mague J T, Fink M J. Facile reductive elimination of ethane from strained dimethylpalladium(II) complexes. J. Am. Chem. Soc., 2001, 123: 4081-4082.
[163] Neve F, Longeri M, Ghedini M, et al. Addition of arenediazonium ligands to a palladium-palladium bond: a reinvestigation. Inorg. Chim. Acta, 1993, 205: 15-22.
[164] Wink D J, Creagan B T, Lee S. Anomalous carbonylation of bis[bis(diphenylphosphino) methane]bis(trifluoroacetato)dipalladium to give an asymmetricμ-CO complex. Inorg. Chim. Acta, 1991, 180: 183-187.
[166] Tsukada N, Tamura O, Inoue Y. Synthesis and structures of palladium and platinum: A-frame complexes bridged by a novel binucleating ligand, N,N-bis[(2-diphenyl phos -phino)phenyl]-formamidine. Organometallics, 2002, 21: 2521-2528.
[165] Kluwe C, Davies J A. Lewis acid catalysis of the rearrangement of a dipalladium acetylene adduct to a vinylidene-bridged complex. Organometallics, 1995, 14, 4257-4262
[167] Chaudret B, Delavaux B, Poilblanc R. Bisdiphenylphosphinomethane in dinuclear complexes. Coord. Chem. Rev., 1988, 86; 191-243.
[168] Puddephatt R J, Manojlovic-Muir L, Muir K W. Coordinatively unsaturated tripalladium and triplatinum clusters: models for reactions on metal surfaces. Polyhedron, 1990, 9: 2767-2802.
[169] Anderson G K. Reactivity of platinum diolefin complexes. 2. Reactions with bulky and chelating Group 5B ligands and studies relating to carbonyl insertion. Adv. Organomet. Chem., 1993, 35, 1-5.
[170] Balch A L. In Homogeneous Catalysis with Metal Phosphine Complexes; Pignolet, L. H., Ed.; Plenum Press: New York, 1983; p 167.5321-5356.
[171] Cox E G, Pinkard F W, Wardlaw W. Synthesis and structures of palladium and platinum A-frame complexes bridged by a novel binucleating ligand, N,N-bis[(2-diphenylphosphino) phenyl]-formamidine. J. Chem. Soc., 1935, 460-4.
[172] Tietze L F, Stewart S G, Polomska M E. Towards a total synthesis of the new anticancer agent mensacarcin: synthesis of the carbocyclic core. Chem. Eur. J., 2004, 10: 5233-5242.
[173] Koeing K. E, Helgeson R C, Cram D J. Synthesis and binding characteristics of macrocyclic polyethers containing convergent methoxyaryl or phenolic groups. J. Am. Chem. Soc., 1976, 98: 4078-4020.
[174] Foster H, Hein D. Notes-phenol-formaldehyde condensation. J. Org. Chem., 1961, 26: 2539-2541.
[175] Wegner G, Nakabayashi N, Cassidy H, Electron-transfer polymers. XXXI. Preparation of difunctional benzoquinones and related derivatives and polymers. J. Org. Chem., 1967, 32: 3155-3159.
[176] Huang W, Gou S H, Hu D H An improved oxidation approach for preparing 4-substituted -2,6-diformylphenol by manganese (IV) dioxide. Synth. Commun., 2000, 30: 1555-1559.
[177] Field L, Hugmark P B, Shumaker S H. Isomerization of aldoximes to amides under substantially neutral conditions. J. Am. Chem. Soc., 1961, 83: 1983-1987.
[178] Ginsburg S, Wilson I B. Oximes of the pyridine series. J. Am. Chem. Soc., 1957, 79: 481-485.
[179] Hassan J, Hathroubi C, Gozzi C. Preparation of unsymmetrical biaryl via palladium catalyzed coupling reation of aryl halides. Tetrahedron, 2001, 57: 7845-7855.
[180] Naiera C, Gil-Molto J, Karlstrom S. Di-2-pyridylmethylamine based palladium complex as new catalysts for Heck, Suzuki, and Sonogashira reactions in organic and aqueous solvent. Org. Lett., 2003, 5: 1451-1454.
[181] Patrick T B, Richard P W, de Gonia W D. Synthesi of biaryls from aryltriazenes. J. Org. Chem., 1985, 50: 2232-2235.
[182] Kitamura Y, Sakurai A, Udzu T. Heterogenous Pd/C-catalyzed ligand-free Suzuki- Miyaura coupling reaction using aryl boronic. Tetrahedron, 2007, 63: 10596-10602.
[183] Martinez-Barrasa V, de Viedma A G, Burgos C. Synthesis of biaryls via intermolecular radical addition of heteroaryl and aryl bromides onto arenes. Org, Lett., 2000, 2: 3933- 3935.
[184] Xiong Z, Wang N D, Dai M J. Synthesis of novel palladacycles and their application in the Heck and Suzuki reaction under aerobic conditions. Org. Lett., 2004, 6: 3337-3340.
[185] Schulz E, Fahmi K, Lemaire M. Synthetic methods for 3-substituted thiophenes. Acros Org. Acta, 1995, 1: 10-17.
[186] Papilon J, Schulz E, Gelinas S. Towards the preparation of modified chiral electrodes for heterogeneous asymmetric catalysis: synthesis and electrochemical properties of (S,S)-5,5'-bis-[3-(3-methylpentyl)-2-thienyl]-[2,2']-bipyridine. Synth. Metals., 1998, 96: 155 -160.
[187] Zhu S S, Swager T M. Design of conducting redox polymers. A polythiophene-Ru (bipy)3n+ hybrid material. Adv. Mater., 1996, 8: 497-500.
[188] Yamamoto T, Maruyama T, Zhou Z. pi-Conjugatedpoly(pyridine-2,5-diyl), poly(2,2'- bipyridine-5,5'-diyl), and their alkyl derivatives. Preparation, linear structure, function as a ligand to form their transition metal complexes, catalytic reactions, n-type electrically conducting properties, optical properties, and alignment on substrates. J. Am. Chem. Soc., 1994, 116: 4832-4845.
[189] Noyori R. Chemical multiplication of chirality: Science and Applications. Chem. Soc. Rev., 1989, 18: 187-208.
[190] Chao Y, Weisman G R, Sogah G D Y. The role of solvation and choice of anion in controlling the thermodynamic stability of the cyclooctatetraene and anthracene dianions. J. Am.Chem. Soc., 1979, 101: 515-519.
[191] Mikes F, Boshart G, Resolution of optical isomers by high-performance liquid chromatography. A comparison of two selector-selectand systems. J. Chromatogr., 1978, 149: 455-464.
[192] Yamamura K, Ono S., Tabushi I. New liquid crystals having 4,4′-biphenanthryl core. Tetrahedron Lett., 1988, 29: 1797-1798.
[193] Bringmann G, Walter R, Weirich R. The direct synthesis of biaryl compound: Modern concepts and strategies. Angew. Chem., Int. Ed. Engl., 1990, 29, 977-979.
[194] Lee D, Kim J, Jun B, Macroporous polystyrene-supported palladium catalyst containing a bulky N-heterocyclic carbene ligand for Suzuki reaction of aryl chlorides. Org. Lett., 2008, 10: 1609-1612.
[195] Vaz B, Pereira R, Perez M. Stereoselective stille coupling of enantiopure haloallenes and alkenylstannanes for the synthesis of allenyl carotenoids. experimental and computational Studies. J. Org. Chem., 2008, 73: 6534-6541.
[196] Kondolff I, Doucet H, Santelli M. Palladium-tetraphosphine as catalyst precursor for high-turnover-number Negishi cross-coupling of alkyl- or phenylzinc derivatives with aryl bromides. Organometallics, 2006, 25: 5219-5222.
[197] Zhang L, Cheng J, Zhang W W. Palladium-catalyzed Kumada reaction employing amino phosphine as ligand. Synth. Commun., 2007, 37: 3809-3814.
[198] Chen S N, Wu W Y, Tsai F Y. Hiyama reaction of aryl bromides with arylsiloxanes catalyzed by a reusable palladium(II)/cationic bipyridyl system in water. Tetrahedron, 2008, 64: 8164-8168.
[199] Ullman F. On a new formation of diphenylamine derivatives. Chem. Ber., 1903, 36: 2389- 2391.
[200] Venkatraman S, Li C J. Carbon-carbon bond formation via palladium-catalyzed reductive Coupling in air. Org. Lett., 1999, 1: 1133-1135.
[201] Venkatraman S, Li C J. The effect of crown-ether on the palladium-catalyzed Ullmann-typecoupling mediated by zinc in air and water. Tetrahedron Lett., 2000, 41, 4831-4832.
[202] Li J H, Xie Y X, Yin D L. New role of CO2 as a selective agent in palladium-catalyzed reductive Ullmann coupling with zinc in water. J. Org. Chem., 2003, 68, 9867-9869.
[203] Mukhopadhyay S, Rothenberg G, Wiener H. Palladium-catalyzed aryl-aryl coupling in water using molecular hydrogen: kinetics and process optimization of a solid-liquid-gas system. Tetrahedron, 1999, 55: 14763-14768.
[204] Mukhopadhyay S, Rothenberg G, Wiener H. Kinetics and mechanism of heterogeneous palladium-catalyzed coupling reactions of chloroaryls in water. J. Chem. Soc., Perkin Trans.2, 1999: 2481-2484.
[205] Mukhopadhyay S, Rothenberg G, Qasheh N. Supported phase-transfer catalysts as selective agents in biphenyl synthesis from haloaryls. Tetrahedron Lett., 2001, 42: 6117-6119.
[206] Ram R N, Singh V. Palladium(II) chloride/EDTA-catalyzed biaryl homo-coupling of aryl halides in aqueous medium in the presence of ascorbic acid. Tetrahedron Lett., 2006, 47: 7625-7628.
[207] Kuroboshi M, Waki Y, Tanaka H, Palladium-catalyzed tetrakis(dimethylamino)ethylene- promoted reductive coupling of aryl halides. J. Org. Chem., 2003, 68: 3938-3942.
[208] Hennings D D, Iwama T, Rawal V H. Palladium-catalyzed (Ullmann-type) homo- coupling of aryl Halides: A convenient and general synthesis of symmetrical biaryls via inter- and intramolecular coupling reactions. Org. Lett., 1999, 1: 1205-1208.
[209] Ma N, Duan Z, Wu Y J. DAB-Cy as an inexpensive and e.ective ligand for palladium- catalyzed homocoupling reaction of aryl halides. J. Organomet. Chem., 2006, 691: 5697- 5700.
[210] Hassen J, Penalva V, Lavenol, L. Catalytic alternative of the Ulimann reaction. Tetrehedron, 1998, 54: 13793-13804.