Catalytic Arylsulfonyl Radical Triggered 1,7-Enyne Bicyclizations

A new metal-free bicyclization reaction
of 1,7-enynes anchored
by α,β-conjugates with arylsulfonyl radicals generated
in situ from sulfonyl hydrazides has been established using tert-butyl hydroperoxide and tetrabutylammonium iodide.
The reactions occurred through sulfonylation/6-exo-dig/6-exo-trig bicyclization/in situ desulfonylation/5-exo-trig cyclization/alkyl or alkenyl migration cascade mechanism
to give benzo­[j]­phenanthridines regioselectively.

一种新型的金属游离型1,7-炔烃的环化反应已成功建立，该反应通过α,β-共轭体系上的芳基磺酰自由基原位生成，自由基来源于磺酰肼。该反应采用叔丁基过氧化氢和四丁基铵碘化物作为催化剂。反应过程通过磺酰化/6-外消旋/6-外环三键环化/原位脱磺酰化/5-外环三键环化/烷基或烯基迁移级联机制进行，从而选择性地生成苯并[j]苯并喹啉。