Reaction of difluorocarbene with propargyl esters and efficient synthesis of difluorocyclopropyl ketones

Difluorocarbene generated from FSO2CF2CO2SiMe3 (TFDA) at 120 °C could reacted with terminal alkynes having an ester group at the α position to the triple bond. Difluorocyclopropenes were further converted to difluorocyclopropyl ketones under alkaline condition. Mechanism for the conversion was studied.