Ortho Palladation and Functionalization of L-Phenylalanine Methyl Ester
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- 作者：José ; Vicente ; Isabel Saura-Llamas ; José ; -Antonio Garcí ; a-Ló ; pez ; Beatrice Calmuschi-Cula ; Delia Bautista
- 刊名：Organometallics
- 出版年：2007
- 出版时间：May 7, 2007
- 年：2007
- 卷：26
- 期：10
- 页码：2768 - 2776
- 全文大小：187K
- 年卷期：v.26,no.10(May 7, 2007)
- ISSN：1520-6041
文摘
The ortho-metalated complex (S,S)-[Pd2{
2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2(
tities/mgr.gif">-Br)2] (1b) can beprepared by refluxing in acetonitrile equimolecular amounts of Pd(OAc)2 and L-phenylalanine methylester hydrochloride, followed by addition of an excess of NaBr. Complex 1b reacts with 4-picoline togive the mononuclear derivative (S)-[Pd{2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2Br(NC5H4Me-4)] (2),whose crystal structure has been determined by X-ray diffraction. The precursor of 1b, (S,S)-[Pd2{2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2(tities/mgr.gif">-Cl)2] (1a), could not be isolated in a pure form, but it can beused as the starting material for the synthesis of functionalized derivatives of the phenylalanine methylester. Thus, CO and RNC (R = Xy, tBu) insert into the Pd-C bond of 1a to afford, after depalladation,(S)-1-oxo-3-(methoxycarbonyl)-1,2,3,4-tetrahydroisoquinoline (3) and (S)-1-R-3-(methoxycarbonyl)-3,4-dihydroisoquinolinium triflate (R = tBu (4), Xy (5)), respectively. Reaction of complex 1b with bromineor iodine affords trans-(S,S)-[PdBr2{NH2CH(CO2Me)CH2C6H4-X-2}2] (X = Br (6), I (7)), which furtherreacts with 1,10-phenanthroline (phen) to give [PdBr2(phen)] and (S)-2-X-phenylalanine methyl ester (X= Br (8), I (9)).
2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2(tities/mgr.gif">-Br)2] (1b) can beprepared by refluxing in acetonitrile equimolecular amounts of Pd(OAc)2 and L-phenylalanine methylester hydrochloride, followed by addition of an excess of NaBr. Complex 1b reacts with 4-picoline togive the mononuclear derivative (S)-[Pd{2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2Br(NC5H4Me-4)] (2),whose crystal structure has been determined by X-ray diffraction. The precursor of 1b, (S,S)-[Pd2{2(C,N)-C6H4CH2CH(CO2Me)NH2-2}2(tities/mgr.gif">-Cl)2] (1a), could not be isolated in a pure form, but it can beused as the starting material for the synthesis of functionalized derivatives of the phenylalanine methylester. Thus, CO and RNC (R = Xy, tBu) insert into the Pd-C bond of 1a to afford, after depalladation,(S)-1-oxo-3-(methoxycarbonyl)-1,2,3,4-tetrahydroisoquinoline (3) and (S)-1-R-3-(methoxycarbonyl)-3,4-dihydroisoquinolinium triflate (R = tBu (4), Xy (5)), respectively. Reaction of complex 1b with bromineor iodine affords trans-(S,S)-[PdBr2{NH2CH(CO2Me)CH2C6H4-X-2}2] (X = Br (6), I (7)), which furtherreacts with 1,10-phenanthroline (phen) to give [PdBr2(phen)] and (S)-2-X-phenylalanine methyl ester (X= Br (8), I (9)).