Palladium-Catalyzed C−C Bond Formation: Synthesis of 1,1-Dialkylbuta-1,3-dienes and β-Phenylstyrenes via Organoboron Intermediates

α,β‐Unsaturated and α‐phenyl acetals show different reactivity when treated with LIC‐KOR superbase and trialkylboranes, in the presence of the reagent system PdL4‐ArX (Suzuki−Miyaura cross‐coupling conditions). In particular, unsaturated acetals yield gem‐dialkylbutadienes via the formation of an intermediate π‐allyl complex that facilitates an anionotropic alkyl migration; in the case of α‐phenyl derivatives, the corresponding cross‐coupling products are recovered. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)