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.
利用
钯催化的加成反应,末端炔、炔酸酯和
锡氢化物构成了以原子经济性方式构建4-
锡基-(E,E)-2,4-二烯酸酯的基本构件。在催化量的
钯(II)
醋酸和三
(2,6-二甲氧基苯基)膦存在下,末端炔与内部炔酸酯发生干净的顺式1,2-加成,生成2-烯-4-炔酸酯。在原位生成的
四(三苯基膦)钯存在下,
锡氢化物对2-烯-4-炔酸酯的
炔烃功能进行反马可夫尼科夫顺式加成。