Regio- and Stereoselective Addition to gem-Difluorinated Ene-Ynamides: Access to Stereodefined Fluorinated Dienes

Org Lett. 2022 Jun 3;24(21):3896-3900. doi: 10.1021/acs.orglett.2c01593. Epub 2022 May 19.

Abstract

The first synthesis of gem-difluorinated ene-ynamides is presented via deprotonation of trifluoromethylated N-allenamides and δ extrusion of fluorine. These highly reactive building blocks, owing to their dual functional groups, offer a unique entry to difluorinated dienes and to stereodefined, monofluoro-substituted dienes. Stereoselective addition to the ynamide moiety led to difluorinated dienes. A stereocontrolled domino δ elimination reaction followed by an addition/elimination sequence from trifluoromethylated N-allenamides provided exclusively stereodefined monofluorinated ene-ynamides.