Assembly of Acyclic All-Carbon Quaternary Stereocenters via Asymmetric Azetidine C–H Borylation and Oxidative Ring-Opening

Reported herein is a one-pot protocol for the asymmetric synthesis of acyclic all-carbon quaternary stereocenters. Iridium-catalyzed enantioselective C(sp³)–H borylation of 3,3-disubstituted azetidines followed by oxidative ring-opening afforded a variety of optically active α,α-disubstituted β-formyl amides. The obtained products could undergo a wide array of downstream transformations, including a formal asymmetric molecular editing approach for the synthesis of 5- to 7-membered saturated azacycles via the insertion of 1–3 carbon units.