Cleavage of carbodicarbenes with N2O for accessing stable diazoalkenes

Abstract

The cleavage of carbophosphinocarbenes and carbodicarbenes with nitrous oxide (N_2O) leads to the formation of room-temperature stable diazoalkenes. The utility of Ph_3P/N_2 and NHC/N_2 ligand exchange reactions were demonstrated by accessing novel benzimidazole- and benzothiazole derived diazoalkenes, which are not accessible by the current state-of-the-art methods. The stable diazoalkenes subsequently allow further ligand exchange reactions at C(0) with carbon monoxide, isocyanide, or a diamidocarbene (DAC). Overall, the combination of hitherto unknown NHC/N_2 and N_2/L (L = DAC, CO, R−NC) ligand exchange reactions at a C(0) center allow the selective functionalization of the carbodicarbene ligand structure which represents a new methodology to rapidly assemble novel carbodicarbenes or cumulenic compounds.