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

Abstract

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 π-allyl-Pd(II) intermediate, depending on the substituents on 1,2-allenyl ketones. The substituted substrate prefers to undergo the π-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.