Isothiouronium-Mediated Conversion of Carboxylic Acids to Cyanomethyl Thioesters.

We report the development of an isothiouronium salt as a reagent for the operationally simple synthesis of cyanomethyl thioesters with high functional group tolerance and avoiding the use of thiols. Additionally, we show that the products can be engaged in amide synthesis in either a two-step or one-pot fashion.