Pyridylalanine (Pal)-Peptide Catalyzed Enantioselective Allenoate Additions to <i>N</i>-Acyl Imines Proceed via an Atypical “aza-Morita−Baylis−Hillman” Mechanism
作者:Lindsey B. Saunders、Bryan J. Cowen、Scott J. Miller
DOI:10.1021/ol101947s
日期:2010.11.5
experiments, including kinetics and hydrogen/deuterium kinetic isotope effects, reveal an “atypical” rate-determining step in a pyridylalanine-peptide catalyzed enantioselective coupling of allenoates and N-acyl imines. Typically, acrylates participate in both the aldehyde-based “Morita−Baylis−Hillman (MBH)” reaction and the imine-based variant (the “aza-MBH”) through similar mechanisms, with proton transfer/catalyst
包括动力学和氢/氘动力学同位素效应在内的机理实验揭示了吡啶基丙氨酸-肽催化的烯丙酸酯和N-酰基亚胺的对映选择性偶联中的“非典型”速率确定步骤。通常,丙烯酸酯通过相似的机制参与基于醛的“ Morita-Baylis-Hillman(MBH)”反应和基于亚胺的变体(“ Aza-MBH”),质子转移/催化剂再生通常是速率决定的。相反,标题反应表现出动力学,其中质子转移在动力学上是沉默的。