DFT computational insight into Pd(0)-catalyzed oxidative cross-coupling of 1,2-allenyl ketones and aryl boronic acids: Pd(ii)-carbenoid intermediate versus π-allyl-Pd(ii) intermediate

DFT calculations unveil that the Pd(0)-catalyzed oxidative cross-coupling of 1,2-allenyl ketones with aryl boronic acids may either occur via a Pd(ii)-carbenoid intermediate or a pi-allyl-Pd(ii) intermediate, depending on the substituents on 1,2-allenyl ketones. The substituted substrate prefers to undergo the pi-allyl-Pd(ii) intermediate mechanism over the Pd(ii)-carbenoid intermediate one, while the unsubstituted one reverses the preference. The calculations also show a new mechanism for the transformation of Pd(0) to the Pd(ii) complex and rationalize the reason for the non-excellent yield for the unsubstituted 1,2-allenyl ketone.

Automated summary

DFT calculations reveal the mechanism preference in the Pd(0)-catalyzed reaction of 1,2-allenyl ketones with aryl boronic acids, dependent on the substituents.