A Facile Preparation of Fluorinated α-Oxoketene Dithioacetals by Using Hexafluoropropene-amine Adduct s

Abstract

Fluorinated α-oxoketene dithioacetals [3] were synthesized in moderate yields by the Lewis acid-promoted reaction of a variety of ketene dithioacetals [1] with hexafluoropropene (HFP)-amine adduct [1a] and/or [1b], derived from morpholine or diethylamine. The use of morpholine adduct gave more satisfactory results than that of diethylamine adduct. Among the Lewis acids employed, boron trifluoride-diethyl ether complex was the most effective for the reaction. The present reaction is strongly subject to steric hindrance caused by the alkyl group on the olefinic carbon atom in [2].