Nitrenic reactivity of diazirines

Abstract

Butyl 3-bromo-3H-diazirine-3-carboxylate (7) and 3-bromo-3-phenyl-3H-diazirine (17) exhibit nitrenic reactivity with phenylmagnesium bromide or tetrabutylammonium cyanide. The formation of several N,N′-disubstituted amidines is attributed to the intermediacy of 1-phenyl or 1-cyano-1H-diazirines possessing a singlet imidoylnitrene character at the N2 atom. Most notably, the reaction of 7 with PhMgBr in diethyl ether affords 2-hydroxy-2,2,N-triphenylacetamidine (9) and 2-methyl-5,5-diphenyl-4-phenylamino-2,5-dihydrooxazole (10) as products derived from nitrene insertion to the ether α-C–H bond.