Total synthesis of bauhinoxepin J: A biologically active dibenzo[b,f]oxepin isolated from bauhinia purpurea

摘要

Bauhinoxepin J possessing antimycobacterial, antimalarial, and tumor growth inhibitory activities was efficiently synthesized. The method involves crucial steps, including a coupling reaction of two aromatic moieties to construct the desired carbon framework, chemoselective phenol oxidation of a bisphenol derivative to establish a key cyclization precursor, and construction of a characteristic seven-membered dihydrooxepin ring by internal cyclization to yield the target bauhinoxepin J. A naturally occurring dibenzo[b,f]oxepin: Bauhinoxepin J was efficiently synthesized starting from two known aromatic moieties. The method features construction of a characteristic dibenzo[b,f]oxepin skeleton through an internal nucleophilic addition/elimination sequence.