ALPHA'-BENZOYLOXY AND ALPHA'-METHOXYMETHOXY LITHIUM ENOLATES GIVING OPPOSITE DIASTEREOFACIAL SELECTIVITIES IN ALDOL REACTIONS - USE OF (PROBABLE) EXTENDED CHELATION FOR REVERSAL OF STEREOSELECTIVITIES

被引：16
作者：
CHOUDHURY, A [1 ]
THORNTON, ER [1 ]
机构：
[1] UNIV PENN,DEPT CHEM,PHILADELPHIA,PA 19104
来源：
TETRAHEDRON LETTERS | 1993年 / 34卷 / 14期
基金：
美国国家卫生研究院;
关键词：
ALDOL; LITHIUM ENOLATE; CHELATION; NONCHELATION; HIGH FACIAL SELECTIVITY;
D O I：
10.1016/S0040-4039(00)77578-2
中图分类号：
O62 [有机化学];
学科分类号：
070303 ; 081704 ;
摘要：
The Li enolates of alpha-benzoyloxy and alpha-methoxymethoxy ketones 1a and 1c afford nonchelation and chelation aldol products, respectively, both with usefully high diastereofacial selectivities. Evidence suggests that transition state chelation of the benzoyl C=O is responsible for the observed ''nonchelation'' stereoselectivity of 1a.
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页码：2221 / 2224
页数：4
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