ADDITION OF A STERICALLY HINDERED, CHIRAL CROTYL ANSA-TITANOCENE COMPLEX TO ALDEHYDES

被引：16

作者：

KUNTZ, BA ^{[1
]}

RAMACHANDRAN, R ^{[1
]}

TAYLOR, NJ ^{[1
]}

GUAN, JY ^{[1
]}

COLLINS, S ^{[1
]}

机构：

[1] UNIV WATERLOO,DEPT CHEM,WATERLOO,ON N2L 3G1,CANADA

来源：

JOURNAL OF ORGANOMETALLIC CHEMISTRY | 1995年 / 497卷 / 1-2期

基金：

加拿大自然科学与工程研究理事会;

关键词：

TITANIUM; ANSA-TITANOCENE; ADDITION TO ALDEHYDES;

D O I：

10.1016/0022-328X(95)00105-Y

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

[S]-1,2-ethylenebis(3-t-butylcyclopendadaienyl)titanium dichloride ([S]-5) can be obtained in high optical purity through kinetic resolution of the racemate (rac-5) using [S]-binaphthol. The structure of rac-1,2-ethylenebis(3-t-butylcyclopentadienyl)titanium binaphtholate (rac-7) was determined by X-ray crystallography: C40H40O2Ti, monoclinic, P2(1)/c, a = 14.455(3) Angstrom, b = 13.710(3) Angstrom, c = 17.278(4) Angstrom, beta = 109.80(2)degrees, V = 3221.7(13) Angstrom, Z = 4, 4599 observed reflections with F greater than or equal to 6 sigma(F), R = 0.0337, R(w) = 0.0359. The addition of [S] = (1-methylallyl)-1,2-ethylenebis(3-t-butylcyclopentadienyl)titanium ([S]-6), formed in situ from [S]-5, to aldehydes was investigated and provides beta-methyl homoallylic alcohols in moderate yields. The stereoselectivity of the reaction and the sense of asymmetric induction depends on the steric bulk of the aldehyde. The results were rationalized using the results of a molecular modelling study on transition state models which reproduced the general trends in the experimental results.

引用

页码：133 / 142

页数：10

共 34 条

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