Stannylative cycloaddition of enynes catalyzed by palladium-iminophosphine

Palladium-iminophosphine complex catalyzes stannylative cycloaddition of conjugated enynes using hexabutyldistannoxane as a stannylating agent to afford highly substituted 3-alkenylphenylstannanes regioselectively. Stannylative cross-cycloaddition reactions between different enynes or between enynes and diynes are also achieved. The reaction is successfully applied to a concise synthesis of alcyopterosin N, which has been isolated recently from sub-Antarctic soft coral, Alcyonium paessleri.