Stereoselective Preparation of (<i>E</i>)- and (<i>Z</i>)-α-Fluorostilbenes via Palladium-Catalyzed Cross-Coupling Reaction of High <i>E</i>/<i>Z</i> Ratio and (<i>Z</i>)-1-Bromo-1-fluoroalkenes
作者:Jianjun Xu、Donald J. Burton
DOI:10.1021/jo060068i
日期:2006.5.1
A highly stereoselective method to prepare both (E)- and (Z)-α-fluorostilbenes is described. 1-Bromo-1-fluoroalkenes (E/Z ≈ 1:1), a readily available starting material, isomerizes to high E/Z ratios by storage at −20 °C or by photolysis at 254 nm. Stille coupling between these high E/Z 1-bromo-1-fluoroalkenes and aryl stannanes gave (Z)-α-fluorostilbenes in high stereoselectivity. (Z)-1-Bromo-1-fluoroalkenes
描述了制备(E)-和(Z)-α-氟丁苯醚的高度立体选择性的方法。1-溴-1-氟烯烃(É / ž ≈1:1),可容易获得的起始原料,异构化成高é / Ž由存储在-20℃下或通过在254nm下光解比率。这些高E / Z 1-溴-1-氟烯烃与芳基锡烷之间的斯蒂勒偶联以高立体选择性产生(Z)-α-氟代苯乙烯。(Z)-1-溴-1-氟烯烃,从动力学上与1-溴-1-氟烯烃分离(E / Z≈1:1),可参与Suzuki偶联反应以立体选择性地产生(E)-α-氟代苯乙烯。