Metal- and O₂‑Free Oxidative C–C Bond Cleavage of Aromatic Aldehydes

An oxidative C–C cleavage of aldehydes requiring neither metals nor O₂ was discovered. Homobenzylic aldehydes and α-substituted homobenzylic aldehydes were cleaved to benzylic aldehydes and ketones, respectively, using nitrosobenzene as an oxidant. This reaction is chemoselective for aromatic aldehydes, as an aliphatic aldehyde was unreactive under these conditions, and other reactive functionality such as ketones and free alcohols are tolerated. A mechanism accounting for the fate of the lost carbon is proposed

Synthesis of Spirooxindoles via the <i>tert</i>-Amino Effect

A new method is developed for the synthesis of spirooxindoles from amines and isatins via C–H functionalization. The reaction leverages the <i>tert</i>-amino effect to form an enolate–iminium intermediate via [1,5]-hydride shift followed by cyclization. Interestingly the hydride migrates to the N atom of a CN, which is atypical for hydride additions to imines