REACTION OF AZOARENES WITH TRIBUTYLTIN HYDRIDE

Tributyltin hydride when reacted with a series of substituted azoarenes afforded hydrazo compounds with high chemoselectivity and good to high yields. With ortho-substituted azoarenes, mixtures of hydrazo derivatives and N-heterocycles or cyclic products only were obtained. The kinetic law of the process was determined in the presence and in the absence of AIBN; with the radical initiator the reaction proceeds via a radical chain mechanism, whereas without AIBN the presence of stannyl free radicals could be discarded. The mechanism of the noninitiated reaction is discussed. EPR characterization of spin adducts obtained by reacting group IVB organometallic radicals with azo compounds is reported.