The Study Of Borono-catellani Arylation Through Palladium/NBE Cooperative Catalysis

The Catellani reaction is known as a powerful strategy that allows the expeditious synthesis of highly substituted arenes and benzo-fused rings.It utilizes the synergistic interaction of palladium and norbornene catalysis to facilitate sequential ortho C-H functionalization and ipso termination of aryl halides in a single operation.In classical Catellani reactions,aryl halides are mainly used as the substrates and a Pd(0)catalyst is required to initiate the reaction.However,recent research advances show that the Catellani reactions can also be initiated by a Pd(?)catalyst with other kinds of substrates instead of aryl halides,including selective C2 functionalization of indoles and pyrroles,meta C-H functionalization of arenes with ortho directing groups,and ortho C-H functionalization of aryl boronic acids and their derivatives(borono-Catellani reaction).This thesis focuses on the study of borono-Catellani reaction and the detail work as follows:We have developed the first intriguing borono-Catellani arylation strategy for unsymmetrical biaryls synthesis,utilizing the readily available pinacol ester of arylboronic acids,aryl bromides and olefins as the reactants.The distinct reactivity of arylboronic esters and aryl bromides enabled the excellent selectivity in the pivotal arylation step.The reaction was promoted by the cooperative catalysis of Pd(OAc)₂ and the readily available NBE derivative N⁷,with molecular oxygen as the terminal oxidant.This mild,scalable,and chemoselective protocol is compatible with a wide variety of functionalized arylboronic esters and aryl bromides,as well as terminating olefins(47examples).Moreover,the chemistry can be extended to the two-component reaction between arylboronic esters and aryl bromides.Preliminary studies revealed the termination could be tuned by the ortho-coordinating group of aryl bromides.