Preparation of Dienylstannanes Via Pd Catalyzed Regio- and Stereocontrolled Addition Reactions

Abstract

Using palladium-catalyzed addition reactions, a terminal alkyne, an alkynoate, and a tin hydride comprise the building blocks for the construction of 4-stannyl-(E,E)-2,4-dienoates in an atom-economical fashion. A terminal alkyne undergoes clean cis-1,2-addition to an internal alkynoate in the presence of catalytic palladium(II) acetate and tris(2,6-dimethoxyphenyl)phosphine to produce a 2-en-4-ynoate. Anti-Markovnikov cis-addition of tin hydride to the acetylenic function of the 2-en-4-ynoate occurs in the presence of in situ generated tetrakis(triphenylphosphine)palladium.