Nonacarbonyldiiron or Pentacarbonyliron Induced Decomposition of Organic Azides and an Azirine. Novel Reduction and Carbonyl Insertion of the Complexed Nitrene Intermediate in Protic Solvents

Article abstract of DOI:10.1246/bcsj.57.1035

The thermal reactions of or the photochemical reactions of with organic azides and an azirine in protic media have been investigated.The thermal reaction of azidobenzene (1) with in methanol under mild conditions gave aniline and methyl phenylcarbamate, along with N,N'-diphenylurea, while in the presence of water, 1 afforded aniline and N,N'-diphenylurea, in good combined yield.Similarly, the thermal reaction of α-azidostyrene (4) with in methanol gave methyl 1-phenylvinylcarbamate and acetophenone which could be derived from the corresponding enamine, while in the presence of water, 4 gave only acetophenone in good yield.The photoirradiation of with 1 or 4 also gave results similar to the -induced reaction.However, the thermal reaction of 3-phenyl-2H-azirine (5) with in methanol gave 2,5-diphenylpyrazine in low yield, in addition to acetophenone and methyl 1-phenylvinylcarbamate, although 5 afforded only acetophenone in the presence of water.The reaction pathways for the formation of the products are discussed on the basis of the formation of a complexed nitrene intermediate, reduction of which induces amine or enamine and carbonyl insertion to yield an organic isocyanate in protic media.