Catalytic Asymmetric α-Aldol Reaction of Vinylogous <i>N</i>-Heterocyclic Carbene Enolates: Formation of Quaternary and Labile Tertiary Stereocenters
作者:Xiuqin Dong、Jianwei Sun
DOI:10.1021/ol500830a
日期:2014.5.2
Simple N-heterocyclic carbene (NHC)-enolates are widely studied versatile species. However, their vinylogous siblings (i.e., vinylogous NHC-enolates) have been much less studied. Here we disclose the first catalytic asymmetric a-aldol reaction of vinylogous NHC-enolates. With trifluoropyruvate as the carbon electrophile, the efficient C C bond formation process displays not only complete alpha-regioselectivity but also excellent stereocontrol over the two newly established challenging stereocenters (one quaternary and the other labile tertiary), furnishing a range of highly enantioenriched beta,gamma-unsaturated alpha-fluoroalkylated esters.