Iridium complex-catalyzed carbonylation of allylic phosphates
作者:Ryo Takeuchi、Yasushi Akiyama
DOI:10.1016/s0022-328x(02)01370-0
日期:2002.5
[Ir(cod)Cl]2 with a ligand such as P(2-furyl)3, PPh2C6F5 or AsPh3 showed high catalytic activity for the carbonylation of allylic phosphates in the presence of alcohols to give the corresponding β,γ-unsaturatedesters. The carbonylation of diethyl (E)-3-phenyl-2-propenyl phosphate in the presence of EtOH under an initial carbon monoxide pressure of 40 kg cm−2 at 100 °C gave ethyl (E)-4-phenyl-3-butenoate
具有配体如P(2-呋喃基)3,PPh 2 C 6 F 5或AsPh 3的[Ir(cod)Cl] 2在醇存在下显示出对烯丙基磷酸羰基化的高催化活性,得到相应的β ,γ-不饱和酯。(E)-3-苯基-2-丙烯基磷酸二乙酯在EtOH存在下于100 kgC的初始一氧化碳压力为40 kg cm -2的羰基化反应得到(E)-4-苯基-3-丁烯酸乙酯收率达90%。否(Z获得)-异构体。不使用胺作为添加剂,反应进行顺利。在EtOH存在下磷酸2-链烯基二乙酯的羰基化反应得到(E)-和(Z)-3-链烯酸乙酯的混合物。起始原料的立体化学通过丢失顺-反插入一氧化碳的进iridiumcarbon键之前中间到π烯丙基铱的异构化。增加烯丙基系统在γ位上的取代基的空间体积,或增加初始一氧化碳压力,将增加对具有与起始原料相同的立体化学的产物的选择性。
γ-Selective allylic substitution reaction with Grignard reagents catalyzed by copper N -heterocyclic carbene complexes and its application to enantioselective synthesis
The reaction of allylic compounds with alkyl Grignard reagents in the presence of a catalytic amount of copper N-heterocyclic carbene (NHC) complexes proceeded predominantly in an SN2′ reaction pathway to give γ-substituted product in excellent yield. The method was applied to asymmetric reaction by using optically active NHC ligands.
The asymmetricallylicsubstitution of allylphosphates with aryl‐ and alkenylboronates catalyzed by a copper/N‐heterocyclic carbene complex was developed and the γ‐substitution products were obtained with high enantioselectivity (see scheme). To account for the observed influence of the reaction parameters a possible catalytic cycle for this process was proposed.