1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric <i>o</i>-Phenylenediamine Substrates
作者:Pawan Thapa、Philip M. Palacios、Tam Tran、Brad S. Pierce、Frank W. Foss
DOI:10.1021/acs.joc.9b02714
日期:2020.2.21
Benzimidazoles are common in nature, medicines, and materials. Numerous strategies for preparing 2-arylbenzimidazoles exist. In this work, 1,2-disubstituted benzimidazoles were prepared from various mono- and disubstituted ortho-phenylenediamines (OPD) by iron-catalyzed oxidative coupling. Specifically, O2 and FeCl3·6H2O catalyzed the cross-dehydrogenative coupling and aromatization of diarylmethyl
Isoindolinone Synthesis: Selective Dioxane-Mediated Aerobic Oxidation of Isoindolines
作者:Pawan Thapa、Esai Corral、Sinjinee Sardar、Brad S. Pierce、Frank W. Foss
DOI:10.1021/acs.joc.8b01920
日期:2019.1.18
N-Alkyl and N-aryl-isoindolinones were prepared by a dioxane-mediated oxidation of isoindoline precursors. The transformation exhibits unique chemoselectivity for isoindonlines. A chiral tertiary (3°)-benzylic position was not racemized during oxidation, and methyl indoprofen was prepared by late stage oxidation. Mechanistic studies suggest a selective H atom transfer, which avoids many known oxidation (by-)products
Metal-Free TEMPO-Promoted C(sp<sup>3</sup>)–H Amination To Afford Multisubstituted Benzimidazoles
作者:Ding Xue、Ya-Qiu Long
DOI:10.1021/jo5005179
日期:2014.5.16
An efficient TEMPO-air/cat. TEMPO-O-2 oxidative protocol was developed to synthesize multisubstituted or fused tetracyclic benzimidazoles via a metal-free oxidative C-N coupling between the sp(3) C-H and free N-H of readily available N-1-benzyl/alkyl-1,2-phenylenediamines.
Subbarayappa, Adimurthy; Patoliya, Paresh U., Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2009, vol. 48, # 4, p. 545 - 552