Enantioselective Morita-Baylis-Hillman Reaction

Significance

This report describes a highly enantioselective and Z-stereocontrolled three-component coupling of α,β-acetylenic esters, aldehydes, and trimethylsilyl iodide (TMSI) using chiral cationic oxazaborolidinium catalysts. Both enantiomers (R/S) of the (Z)-β-iodo Morita-Baylis-Hillman (MBH) ester product could be obtained enantioselectively by using the chiral catalysts 1a and its enantiomer. The subsequent metal-catalyzed cross-coupling of these esters were performed directly with retention of configuration to afford synthetically more useful β-branched MBH esters.