Stereoselective Synthesis of Monofluoroalkyl α,β-Unsaturated Ketones From Allenyl Carbinol Esters Mediated by Gold and Selectfluor

Allenyl carbinol ester 3 isomerizes to an E,Z mixture of the corresponding diene 2 in the presence of gold catalyst 4, but the resulting mixture yields monofluoroalkyl α,β-unsaturated ketone 1 with exclusive E selectivity and in high yields after reaction with Selectfluor.