Ni(0)-Catalyzed Rearrangement of Vinylcyclobutanones (VCBOs) to Synthesize Six-Membered Non-Conjugated Enones.

We report here the first nickel-catalyzed rearrangement of vinylcyclobutanones (VCBOs) under mild conditions to synthesize non-conjugated cyclohexenone derivatives, which so far do not have many ways to be accessed. The reaction exhibits a wide substrate scope with reaction yields up to 98%. This VCBO rearrangement can also be used to access various n/6 (n = 5-8) bicyclic products efficiently. Furthermore, mechanism of this rearrangement has been investigated using DFT calculations, showing that vinyl group-assisted cyclobutanone C-C cleavage is easy with a computed activation free energy of 18.1 kcal/mol.