Mechanistic Implications in the Morita−Baylis−Hillman Alkylation: Isolation and Characterization of an Intermediate
作者:Marie E. Krafft、Thomas F. N. Haxell、Kimberly A. Seibert、Khalil A. Abboud
DOI:10.1021/ja057595o
日期:2006.4.5
An intermediate phosphonium salt has never been isolated from the Morita-Baylis-Hillman (MBH) reaction. Due to the weakly basic counterion produced in the MBH alkylation and allylation reactions, the reaction can be stopped after electrophilic attack on the zwitterionic enolate and an intermediate isolated. Upon analysis of the crystal structure, a trans geometry is observed, suggesting that there is no electrostatic interaction between phosphorus and oxygen in the zwitterionic enolate that undergoes alkylation, thus giving new mechanistic insight into the MBH reaction.