Mild and efficient synthesis of carbazates and dithiocarbazates via a three-component coupling using Cs2CO3 and TBAI

Efficient methods for the synthesis of carbazates and dithiocarbazates have been developed. In the presence of cesium carbonate (Cs2CO3) and tetrabutylammonium iodide (TBAI) a hydrazine, CO2 or CS2, and an alkyl halide underwent a three-component coupling at room temperature. Various unprotected hydrazines and alkyl halides were examined and the results demonstrated this methodology was highly chemoselective. Applications toward the synthesis of azadepsipeptides and other pseudopeptides are described.