Catalyst Control in Positional-Selective C–H Alkenylation of Isoxazoles and a Ruthenium-Mediated Assembly of Trisubstituted Pyrroles
作者:Pravin Kumar、Manmohan Kapur
DOI:10.1021/acs.orglett.9b00446
日期:2019.4.5
determining the positional selectivity in C–H alkenylation of isoxazoles. A cationic rhodium-mediated, strong-directing group promotes C(sp2)-H activation at the proximal aryl ring whereas, the palladium-mediated electrophilic metallation leads to the C(sp2)-H activation at the distal position of the directing group. Synthetic elaboration of this C–H alkenylation product via ruthenium and copper co-catalysis
在确定异恶唑的CH链烯基化反应中的位置选择性方面,证明了高水平的催化剂控制能力。阳离子铑介导的强方向性基团在近端芳基环处促进C(sp 2)-H活化,而钯介导的亲电金属化作用则在该方向的远端位置导致C(sp 2)-H活化团体。通过钌和铜的共催化合成这种C–H链烯基化产物,可得到一种高效的方法,用于组装密集取代的吡咯。