Pattarawarapan M, Yamano D, Wiriya N, Yimklan S, Phakhodee W. Simultaneous Formation and Functionalization of Aryliminophosphoranes Using 1,3-Dihydro-1
H-benzimidazol-2-ones as Precursors.
J Org Chem 2020;
85:13330-13338. [PMID:
33006471 DOI:
10.1021/acs.joc.0c01979]
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Abstract
An atom- and step-economic synthesis of aryliminophosphoranes bearing ortho urea was achieved via unprecedented Ph3P-I2 mediated ring-opening of 1,3-dihydro-1H-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 N1-substituted 2-aminobenzimidazoles as well as fused tetracyclic quinazolinone derivatives in one-pot. 31P{1H} NMR studies suggested that the urea C-N bond of benzimidazolone is weakened by N-phosphorylation, leading to aminolysis rather than the expected deoxygenative amination.
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