Controllable carbonyl-assisted C(sp3)–C(sp3) bond reduction and reorganization

Abstract

C–C bond reduction and reorganization are fundamentally important in organic synthesis. However, there are no practical methods for tandem C–C reduction and reorganization. Here we report a versatile approach for selective reduction of the unstrained C(sp³)–C(sp³) bond of ketones, including hydrogenolytic [2 + 2 + 2]-cycloreversion of 2,4-diaroylcyclohexanols, without requiring protecting groups or hydrogen gas. Mechanistic data demonstrate that the C–C cleavage occurs via a bimetallic pathway, and nucleophile trapping of the resulting enone is crucial for C–C reduction relay. Moreover, a practical strategy for intramolecular C–C cascade reorganization is established via iterative retro-Michael/intramolecular Michael addition sequence, thus enabling cyclizative degradation of poly(vinylketone) to trisubstituted cyclohexanes. These results could open new prospects for unstrained C(sp³)–C(sp³) bond disconnection and reconstruction.