Imidoyl radicals 4a-d, obtained by hydrogen abstraction from imines 1a-d, give 7-membered cyclisation leading to oxazapines 2a-d. The intermediate spirocyclohexadienyl radicals of the competitive 6-membered ring closure (6a-d) rearrange to aryloxy radicals, giving benzophenones 3a-d: the whole process entails a novel 1,5-aryl radical translocation from an oxygen to a carbon atom.
Late-Stage Two-Step C11─H Arylation of Dibenzooxa/thiazepines
作者:Yang Chen、Mengyao Ma、Hongguang Du、Jiaxi Xu、Zhanhui Yang
DOI:10.1055/a-2038-2323
日期:——
A practical and efficientsynthesis of 11-aryldibenzooxa/thiazepines is achieved, via a late-stage and two-step C11–H arylation of simple dibenzooxa/thiazepines. The adoption of Grignard addition and DDQ dehydrogenation allows for operationally simple and chemically reliable, step-efficient, and high-yielding transformations. The two-step and one-pot procedures provide excellent yields. The gram-scale