Construction of benzimidazole-fused dihydrobenzoxazoles via Cu-catalyzed tandem C–H functionalization

Abstract

Benzimidazole-fused dihydrobenzoxazoles are an important class of complex heterocycles containing both nitrogen and oxygen as building blocks for materials and pharmaceuticals. Traditional synthetic method for the skeleton lacks of step economy. This article describes the tandem cyclization of 1H-benzimidazole and 2-bromophenol catalyzed by copper(II) via N-arylation/sp 2 C−H activation/C−O bond cyclization to construct benzimidazole-fused dihydrobenzoxazoles in one-pot. The reaction was carried out under an air atmosphere with simple reactive conditions and easy handling. In addition, other benzimidazole derivatives, as well as 2-iodophenol and 2-hydroxybenzeneboronic acid, are also suitable for this reaction. This transformation provides a convenient method to synthesize a series of benzimidazole-fused dihydrobenzoxazoles.

The Origins of Low‐Fracture Conductivity in Soft Shale Formations: An Experimental Study

“…Then, the JRC is given by its empirical relationship to D [Eq. (10)]: [35] JRC ¼ 85:2671ðDÀ1Þ 0:5679 ð10Þ…”