Merging “Anti-Baldwin” 3-Exo-Dig Cyclization with 1,2-Alkynyl Migration for Radical Alkylalkynylation of Unactivated Olefins

Qi Zhao, Xiao-Shuang Ji, Yi-Yun Gao, Wen-Juan Hao,* Ke-Ying Zhang, Shu-Jiang Tu,* Bo Jiang*

A new combination of “anti-Baldwin” 3-exo-dig cyclization with 1,2-alkynyl migration of 1,4-enynes with simple cycloal-kanes was established, enabling C-C breaking and reconstruction to access a wide range of α-alkynyl ketones with generally good yields by FeCl₂/ di-tert-butyl peroxide (DTBP) as catalytic oxidation system. Radical-induced C(sp³)–H functionaliza-tion of cycloalkanes was realized, leading to the direct formation of C(sp³)–C(sp³) and C(sp)–C(sp³) bonds. The mechanism for forming α-alkynyl ketones was proposed.

Org. Lett. 2018, 20, 3596-3600