Application of modular nucleophilic glycine equivalents for truly practical asymmetric synthesis of β-substituted pyroglutamic acids
作者:Vadim A. Soloshonok、Hisanori Ueki、Trevor K. Ellis、Takeshi Yamada、Yasufumi Ohfune
DOI:10.1016/j.tetlet.2004.12.093
日期:2005.2
A new series of achiral glycine equivalents have been evaluated with respect to their synthetic utility for the production of beta-substituted pyroglutamic acid derivatives. Among them, the piperidine-de rived complex was found to be a superior glycine derivative for the Michael additions with various (R)-N-(E-enoyl)-4-phenyl-1,3-oxazolidin-2-ones representing a general and practical synthesis of sterically constrained beta-substituted pyroglutamic acids. In particular, application of complex allowed for the first time preparation of the corresponding isopropyl derivatives thus increasing the synthetic efficiency and expanding generality these Michael addition reactions. (C) 2004 Elsevier Ltd. All rights reserved.