Cascade Detrifluoroacetylation, C-S Bond Cleavage, and SN2' 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 PhSO2CF2 anion, C-S bond cleavage to generate a sulfonyl anion with the release of CF2 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 beta,gamma-unsaturated sulfones.

Automated summary

A new S(N)2' reaction type between MBH ester and sulfonyl anion has been developed, in which the sulfonyl anion is generated in situ via detrifluoroacetylation. The reaction proceeds through C-C and C-S bond cleavage to generate corresponding anions, which then react with the MBH ester. The reaction features operational simplicity, wide substrate scope, high yields, and excellent stereoselectivity, providing an efficient way to obtain beta,gamma-unsaturated sulfones.