A Carboxylative Cyclization of Propargylic Amines with Carbon Dioxide Catalyzed by the N‐Heterocyclic Carbene 1,3‐Di‐tert‐butylimidazol‐2‐ylidene (ItBu)

Abstract

AbstractBy employing N‐heterocyclic carbenes (NHCs) as catalysts, the carboxylative cyclization of propargylic amines proceeded under atmospheric pressure of CO2 (0.1 MPa) to afford the corresponding 2‐oxazolones as the main products. It was considered that the carboxylative cyclization of propargylic amines with CO2 proceeded to initially provide 2‐oxazolidinones, after which the generated 2‐oxazolidinones were consecutively tautomerized to give the corresponding 2‐oxazolones. Moreover, we could perform the NHC‐catalyzed carboxylative cyclization of propargylic amines to provide 2‐oxazolidinones or 2‐oxazolones selectively under controlled reaction conditions.