Palladium-Catalyzed Silylation of 2,3-Allenols with Unactivated Disilanes: Access to 2-Silyl-1,3-butadienes and α-Silyl-β-hydroxy Vinylsilanes.

Regioselective silylation of 2,3-allenols with disilanes was carried out under catalysis of Pddba/P(-MeOCH). In the presence of CsCO, the reaction achieved 2-silyl-1,3-dienes. Reaction of 1-aryl-2,3-allenols gave the products with excellent / selectivity and -isomers as the major species. Reaction of α-alkylallenols or α-alkyl-α-aryl-allenols resulted in products with moderate / selectivity and -isomers are also major. Without a base, the reaction produced α-silyl-β-hydroxyl vinylsilanes, which were converted to 2-silyl-1,3-dienes upon treatment with CsCO.