Esterification of Thioamides via Selective N-C(S) Cleavage under Mild Conditions.

Herein, we report an exceedingly mild method for the direct, transition-metal-free esterification of thioamides through the selective generation of tetrahedral intermediates. The method represents the first transition-metal-free approach to the thioamide to thionoester transformation in organic synthesis. This reactivity has been accomplished through -Boc-thioamides that engage in ground-state destabilization of the n → π* conjugation. The ground-state destabilization of "single-atom" bioisosteric thioamides will expand the arsenal of valuable amide bond functionalization reactions.