Deoxygenative Tri- and Difluoromethylthiolation of Carboxylic Acids with Benzothiazolium Reagents

Org Lett. 2020 Nov 20;22(22):8925-8930. doi: 10.1021/acs.orglett.0c03328. Epub 2020 Nov 4.

Abstract

Deoxygenative syntheses of fluorinated thioesters directly from carboxylic acids have been developed employing benzothiazolium reagents. The process using BT-SCF3 represents an attractive approach toward these SCF3-containing compounds that avoids the use of metal -SCF3 salts or preactivated acyl electrophiles. Moreover, the in situ activation of BT-SCF2H 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 -SCF2H anion.