Alkyne and Reversible Nitrile Activation: N,N '-Diamidocarbene-Facilitated Synthesis of Cyclopropenes, Cyclopropenones, and Azirines

Abstract

We report the synthesis of a variety of diamidocyclopropenes by combining an isolable and readily accessible N,N'-diamidocarbene (DAC) with a range of alkynes (nine examples, 68-97% yield). Subsequent hydrolysis of selected cyclopropenes afforded the corresponding cyclopropenones or alpha,beta-unsaturated acids, depending on the reaction conditions. In addition, the combination of a DAC with alkyl or aryl nitriles was found to form 2H-azirines in a reversible manner (four examples, K-eq = 4-72 M-1 at 30 degrees C in toluene).