Behaviors of α-Fluorocarbenoids Derived from the Nucleophilic Desulfinylation of α-Chloro-α-fluoroalkyl Sulfoxides

Abstract 2-Aryl-1-chloro-1-fluoroethyl sulfoxides underwent nucleophilic desulfinylation with PhMgBr to give (Z)-fluorostyrene derivatives in a very stereoselective manner (> 33 : 1) via an α-fluorocarbene species. When treated with 3 equiv of PhLi in the presence of N,N,N′,N′-tetramethylethylenediamine, they similarly formed fluorostyrenes as a stereoisomeric mixture (E : Z = 2 : 1), but with 1 equiv of PhLi 2-aryl-1-chloro-1-fluoroethanes were the major product. On the other hand, no formation of a fluoroalkene was observed in the desulfinylation of 1-chloro-1-fluoro-4-phenylbutyl sulfoxide with the nucleophiles. In the latter reaction, oxidation and/or phenylation of the intermediate carbene were the main pathways.