Photocatalytic Multisite Functionalization of Unactivated Terminal Alkenes by Merging Polar Cycloaddition and Radical Ring‐Opening Process
Haidong Liu, Yipeng Wang, Hui Wang, Kewei Ren, Longfei Liu, Luzhen Dang, Cheng‐Qiang Wang, Chao Feng
Abstract
Abstract Although highly appealing for rapid access of molecular complexity, multi‐functionalization of alkenes that allows incorporation of more than two functional groups remains a prominent challenge. Herein, we report a novel strategy that merges dipolar cycloaddition with photoredox promoted radical ring‐opening remote C(sp 3 )−H functionalization, thus enabling a smooth 1,2,5‐trifunctionalization of unactivated alkenes. A highly regioselective [3+2] cycloaddition anchors a reaction trigger onto alkene substrates. The subsequent halogen atom transfer (XAT) selectively initiates ring‐opening process, which is followed by a series of 1,5‐hydrogen atom transfer (1,5‐HAT) and intermolecular fluorine atom transfer (FAT) events. With this method, site‐selective introduction of three different functional groups is accomplished and a broad spectrum of valuable β‐hydroxyl‐ϵ‐fluoro‐nitrile products are synthesized from readily available terminal alkenes.