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.