α,β-Unsaturated Acyl Azoliums from N-Heterocyclic Carbene Catalyzed Reactions: Observation and Mechanistic Investigation
作者:Jessada Mahatthananchai、Pinguan Zheng、Jeffrey W. Bode
DOI:10.1002/anie.201005352
日期:2011.2.11
Caught in the act: Acyl azoliums have long been thought to be key reactive intermediates in N‐heterocycliccarbene catalysis, but they have never been observed under catalytic conditions. Now, this has been successfully achieved by the characterization of α,β‐unsaturated acyl azoliums (see scheme) using different spectroscopic techniques. Kinetic studies revealed the origin of their unexpected chemoselectivity