On the role of chiral catalysts in the alkenyl zirconocene/zinc addition to aldehydes: A study of ligand loading and asymmetric amplification

被引：27

作者：

Wipf, P ^{[1
]}

Jayasuriya, N ^{[1
]}

Ribe, S ^{[1
]}

机构：

[1] Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA

来源：

CHIRALITY | 2003年 / 15卷 / 03期

关键词：

nonlinear effects; chiral allylic alcohols; aminothiophenol; aminophenol; aminoalcohol; ligand aggregation; dimethylzinc; transmetalation; chiral induction; catalysis;

D O I：

10.1002/chir.10176

中图分类号：

R914 [药物化学];

学科分类号：

100701 ;

摘要：

Unusual nonlinear asymmetric amplification and chiral ligand loading effects were discovered for the use of catalytic quantities of chiral aminoalcohols in the in situ hydrozirconation-transmetalation-aldehyde addition processes. While the stereochemically most efficient aminothiol ligands demonstrated mechanistically conventional reaction parameters in excellent agreement with Kagan's ML2 system, the asymmetric induction in the presence of a chiral aminoalcohol was found to vary greatly with loading and %ee of the ligand. Aminothiols remain the ligands of choice for the highly enantioselective formation of allylic alcohols and provide experimentally more predictable reaction variables. However, new, optimized conditions lead to a synthetically useful product %ee using the readily available and scalable aminoalcohol 2a. (C) 2003 Wiley-Liss, Inc.

引用

页码：208 / 212

页数：5

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