Azobisisobutyronitrile-Initiated Oxidative C–H Functionalization of Simple Alcohols with Diaryl(arylethynyl)phosphine Oxides: A Metal-Free Approach toward Hydroxymethyl Benzo[b]phosphole Oxides and 6H‑Indeno[2,1‑b]phosphindole 5‑Oxide Derivatives

The first metal-free and facile radical addition/cyclization of simple alcohols with diaryl­(arylethynyl)­phosphine oxides has been described with azobisisobutyronitrile as a radical initiator, affording an efficient and one-pot procedure to access a new class of hydroxymethyl benzo­[b]­phosphole oxides and 6H-indeno­[2,1-b]­phosphindole 5-oxides for potential application in organic materials via sequential C­(sp3)–H/C­(sp2)–H functionalization. The method employs easily accessible starting materials and is endowed with high regioselectivity and broad functional-group tolerance.