Carbenoids with Sulfinate as Nucleofuge for Matteson‐Type Homologation: Direct Insertion of Oxygen‐ and Nitrogen‐Substituted Units into Carbon‐Boron Bonds

Abstract Carbenoid insertion into boronate carbon‐boron bonds, namely the Matteson‐type homologation, has been recognized as a powerful tool for constructing carbon‐carbon bonds. However, some limitations and inconvenience still exist with the carbenoids currently employed, such as the use of highly cryogenic and basic conditions. Herein, we report a new class of stable carbenoids with sulfinate as nucleofuge for Matteson‐type homologations, which directly introduce O‐ and N‐substituted methylenes into carbon‐boron bonds. Enabled by oxazaborolidines as the boronic substrates, the reaction is operatable at 0 °C or room temperature with weaker bases. Broad functional groups, including acidic C−H bonds, can be tolerated. The synthetic utility of this method has been demonstrated in the gram‐scale synthesis and iterative insertion of various carbenoids.