Simultaneous Formation and Functionalization of Aryliminophosphoranes Using 1,3-Dihydro-1-benzimidazol-2-ones as Precursors.

An atom- and step-economic synthesis of aryliminophosphoranes bearing urea was achieved via unprecedented PhP-I mediated ring-opening of 1,3-dihydro-1-benzimidazol-2-ones with secondary amines. Tandem aza-Wittig/heterocyclization of the functionalized aryliminophosphoranes upon treatment with isothiocyanates enables a facile access to a single regioisomer of -substituted 2-aminobenzimidazoles as well as fused tetracyclic quinazolinone derivatives in one-pot. P{H} NMR studies suggested that the urea C-N bond of benzimidazolone is weakened by -phosphorylation, leading to aminolysis rather than the expected deoxygenative amination.