One catalyst for two distinct reactions: sequential asymmetric hetero Diels–Alder reaction and diethylzinc addition
作者:Haifeng Du、Xue Zhang、Zheng Wang、Kuiling Ding
DOI:10.1016/j.tet.2005.08.007
日期:2005.10
addition to the benzaldehyde, affording the corresponding secondary alcohol with up to 94.5% ee under optimized conditions. On the basis of these facts, the integration of two distinct enantioselective reactions, HDA and diethylzinc addition reactions, has been realized in one-pot with the promotion of a single chiral zinc catalyst in a sequential manner. The impact of diimine additive on the catalytic system
本文介绍了成功开发出一系列包含(R)-3,3'-Br 2 -BINOL配体和各种二亚胺活化剂的手性锌催化剂,通过组合方法使Danishefsky's二烯与醛的对映选择性HDA反应,得到相应的2 ,3-二氢-4 H-pyran-4-one衍生物,具有出色的收率和对映选择性。这类催化剂的应用范围也扩大到了苯甲醛中的二乙基锌加成反应,从而在优化的条件下得到了相应的仲醇,其ee含量高达94.5%。基于这些事实,已经实现了两个不同的对映选择性反应,即HDA和二乙基锌加成反应的整合,并且以顺序的方式促进了一种手性锌催化剂的整合。通过探索反应体系的非线性效应,研究了二亚胺添加剂对HDA反应催化体系的影响。催化体系中表现出的正非线性效应可归因于杂手性锌物质的不良溶解性。概述了Danishefsky二烯与醛的2- BINOL / Zn /二亚胺催化的对映选择性HDA反应。