Pd-Catalyzed Formal [2 + 2]-Retrocyclization of Cyclobutanols via 2-Fold Csp 3 -Csp 3 Bond Cleavage.

In this work, we describe the unexpected 2-fold Csp 3 -Csp 3 bond cleavage suffered by cyclobutanols in the presence of a catalytic amount of Pd(OAc) 2 and promoted by the bulky biaryl JohnPhos ligand. Overall, the sequential cleavage of a strained and an unstrained Csp 3 -Csp 3 bond leads to the formal [2 + 2]-retrocyclization products, namely, styrene and acetophenone derivatives. This procedure might enable the use of cyclobutanols as masked acetyl groups, resisting harsh conditions in organic synthesis.