Deoxygenative Tri- and Difluoromethylthiolation of Carboxylic Acids with Benzothiazolium Reagents.

Deoxygenative syntheses of fluorinated thioesters directly from carboxylic acids have been developed employing benzothiazolium reagents. The process using BT-SCF represents an attractive approach toward these SCF-containing compounds that avoids the use of metal SCF salts or preactivated acyl electrophiles. Moreover, the activation of BT-SCFH allows for an unprecedented nucleophilic difluoromethylthiolation reaction. DFT calculations support a mechanistic scenario involving a four-membered transition state where acyl substitution occurs without the formation of an unstable free SCFH anion.