Cascade Detrifluoroacetylation, C-S Bond Cleavage, and S N 2' Reaction of α,α-Difluorinated Gem -Diols with MBH Esters.

A new S N 2' reaction type of Morita-Baylis-Hillman (MBH) ester with sulfonyl anion, generated in situ via detrifluoroacetylation as a nucleophile is developed. Experimental results and DFT calculations disclose that the reaction proceeds via C-C bond cleavage to generate a PhSO 2 CF 2 anion, C-S bond cleavage to generate a sulfonyl anion with the release of CF 2 carbene, and an S N 2' reaction with the MBH ester. The reaction features operational simplicity, wide substrate scope, high yields, and excellent stereoselectivity, which represents a new reaction mode of fluorinated gem -diols and also provides an efficient way to obtain β,γ-unsaturated sulfones.