Rh-catalyzed asymmetric Suzuki-Miyaura allylation of vinylcyclobutanols toward axially chiral alkylidenecyclobutanes

Asymmetric allylic substitution (AAS) reactions are well-established for constructing chiral molecules. However, the utilization of non-activated tertiary allylic electrophiles in AAS reactions remains challenging, primarily due to difficulties in controlling both enantio- and regioselectivity while activating sterically congested substrates. Herein, we disclose a rhodium-catalyzed asymmetric allylic arylation of achiral vinylcyclobutanols with arylboroxines, delivering axially chiral alkylidenecyclobutanes with exclusive γ-regioselectivity. The catalytic system employs [Rh(chiral diene)OAc]2 and a catalytic weak base (CsOAc), which is essential for activating the vinylcyclobutanols toward AAS reaction while preserving the strained ring framework. This Suzuki-Miyaura allylation utilizes free hydroxy group as the leaving group, enabling exceptional γ-selectivity in tertiary allylic alcohol substitutions and simultaneous construction of axial chirality within four-membered carbocycles containing tertiary or all-carbon quaternary stereocenters.