Preparation and X-ray Structures of Alkyl-Titanium(IV) Complexes Stabilized by Indenyl Ligands with a Pendant Ether or Amine Substituent and Their Use in the Catalytic Hydroamination of Alkynes

详细信息    查看全文

• 作者：Marí ; a L. Buil ; Miguel A. Esteruelas ; Ana M. L&oacute ; pez ; A. Concepci&oacute ; n Mateo ; Enrique O&ntilde ; ate
• 刊名：Organometallics
• 出版年：2007
• 出版时间：January 29, 2007
• 年：2007
• 卷：26
• 期：3
• 页码：554 - 565
• 全文大小：282K
• 年卷期：v.26,no.3(January 29, 2007)
• ISSN：1520-6041

文摘

Complexes Ind^XTiCl₃ (1, 2) react with 1.0, 2.0, and 3.0 equiv of MeMgCl to give Ind^XTiMeCl₂ (3, 4),Ind^XTiMe₂Cl (5, 6), and Ind^XTiMe₃ (7, 8), respectively (X = CH₂CH₂OMe (1, 3, 5, 7), CH₂CH₂NMe₂(2, 4, 6, 8)). Complexes 3, 6, and 8 have been characterized by X-ray diffraction analysis. The structuresprove that in the solid state the pendant substituents of the indenyl ligands are coordinated to the metalcenter (d(Ti-O) = 2.296(3) Å (3); d(Ti-N) = 2.4006(19) (6), 2.4214(17) Å (8)) disposed transoid to amethyl ligand. In solution the pendant donor groups are involved in coordination-dissociation equilibria(mages/gifchars/Delta.gif" BORDER=0 >Hmages/entities/deg.gif"> = 4.2 ± 0.6 kcal mol^-1 and mages/gifchars/Delta.gif" BORDER=0 >Smages/entities/deg.gif"> = 15.5 ± 3 eu for 3; mages/gifchars/Delta.gif" BORDER=0 >Hmages/entities/deg.gif"> = 3.4 ± 0.2 kcal mol^-1 and mages/gifchars/Delta.gif" BORDER=0 >Smages/entities/deg.gif"> =11.6 ± 0.3 eu for 4; mages/gifchars/Delta.gif" BORDER=0 >Hmages/entities/deg.gif"> = 3.5 ± 1.1 kcal mol^-1 and mages/gifchars/Delta.gif" BORDER=0 >Smages/entities/deg.gif"> = 15.2 ± 4.4 eu for 5; mages/gifchars/Delta.gif" BORDER=0 >Hmages/entities/deg.gif"> = 4.3 ± 1.3 kcalmol^-1 and mages/gifchars/Delta.gif" BORDER=0 >Smages/entities/deg.gif"> = 16.0 ± 2.8 eu for 6; mages/gifchars/Delta.gif" BORDER=0 >Hmages/entities/deg.gif"> = 2.2 ± 0.5 kcal mol^-1 and mages/gifchars/Delta.gif" BORDER=0 >Smages/entities/deg.gif"> = 11.0 ± 2.2 eu for 7; mages/gifchars/Delta.gif" BORDER=0 >Hmages/entities/deg.gif">= 4.9 ± 0.5 kcal mol^-1 and mages/gifchars/Delta.gif" BORDER=0 >Smages/entities/deg.gif"> = 20.8 ± 2.2 eu for 8). Complexes 7, 8, IndTiMe₃ (9), and H₄IndTiMe₃(10; H₄Ind = 4,5,6,7-tetrahydroindenyl) are efficient catalyst precursors for the regioselective hydroamination of 1-octyne, phenylacetylene, and 1-phenylpropyne with aromatic (2,6-dimethylaniline and 2,6-diisopropylaniline) and aliphatic (tert-butylamine, dodecylamine, and cyclohexylamine) amines. Thereactions give imine or imine-enamine mixtures, which are reduced to the corresponding secondaryamines. The Markovnikov or anti-Markovnikov nature of the obtained products depends on the aliphaticor aromatic character of both the alkyne and the amine. Markovnikov products with regioselectivities of100% are formed from the reactions between 1-octyne and aromatic amines, while anti-Markovnikovderivatives with regioselectivities of 100% are obtained from the reactions of aromatic alkynes with allthe studied amines and from the reactions of 1-octyne with tert-butylamine and dodecylamine. The reactionsof 1-octyne with cyclohexylamine give mixtures of both types of products. A comparative study betweenthe catalytic efficiencies of 7-10 and those of their cyclopentadienyl counterparts is also included (Table4).