Manganese(III)-mediated cyclodimerization of a hydrazinyl derivative generating an unprecedented 1,2,3,5,6-substituted leuco-verdazyl ring.

The one-pot reaction of Mn(OAc)(3) with two equivalents of 6-(pyridine-2-ylhydrazonomethyl)phenol (Hphp) in methanol leads to a unique leuco-verdazyl-type ring. The remarkable cyclodimerization reaction is proposed to involve a number of one-electron oxidative steps mediated by Mn(3+) ions, as well as a very uncommon 1,2-radical aryl migration and a nucleophilic attack of the solvent, i.e. methanol.

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