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

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.