Fully palladium/copper catalytic oxidative cross-coupling of acrylates with α-methylstyrene was performed in a DMSO/AcOH (1:1) mixture at 60 °C in the air. This improves previous procedures which employed stoichiometric amounts of copper and oxygen. Thus various acrylates were effectively coupled to α-methylstyrene giving the expected compounds in moderate to good yields (44%–65%) as a mixture of E and Z isomers.
丙烯酸酯与 α-甲基苯乙烯的全钯/铜催化氧化交叉偶联反应是在 DMSO/AcOH (1:1) 混合物中于 60 °C 空气中进行的。这改进了以往采用铜和氧的化学计量方法。因此,各种丙烯酸酯都能有效地与α-甲基苯乙烯偶联,并以中等至良好的收率(44%-65%)得到预期的 E 和 Z 异构体混合物。
Synthesis of Conjugated Dienes via a Biomimetic Aerobic Oxidative Coupling of Two C<sub>vinyl</sub>H Bonds
作者:Nicolas Gigant、Jan-E. Bäckvall
DOI:10.1002/chem.201301771
日期:2013.8.12
A time to dienes: A highly efficient and general method has been developed to prepare conjugateddienes through a biomimetic approach. This aerobic oxidative coupling, involving two CvinylH bonds, proceeds under low Pd catalyst loading and employs catalytic amounts of p‐benzoquinone and iron phthalocyanine as electron‐transfer mediators (ETMs) under ambient oxygen pressure (see scheme).