An Efficient and General Route to <i>g</i><i>em</i>-Difluoromethylenated α,β-Unsaturated δ-Lactones: High Enantioselective Synthesis of <i>g</i><i>em</i>-Difluoromethylenated Goniothalamins
An efficient and general strategy to gem-difluoromethylenated α,β-unsaturated δ-lactones in high yields from various aldehydes (including aliphatic, aromatic, α,β-unsaturated, and sterically hindered aldehydes) has been developed. This methodology was successfully applied for the preparation of two enantiomers of gem-difluoromethylenated goniothalamins (S)-1 and (R)-1. gem-Difluoropropargylation of