Imine Ring Of The Ferrocene Palladium Compounds And Their Phosphine Adducts Boron Esterification Reaction And Suzuki-miyaura

We studied the synthesis and characterization of phosphine adducts of cyclopalladated ferrocenylimine and their applications in the synthesis of arylboronate esters and the BSC (borylation/Suzuki-Miyaura coupling) reaction.1. Synthesis of phosphine adducts of cyclopalladated ferrocenylimineâ…¡a-f.A series phosphine adducts of cyclopalladated ferrocenylimineâ…¡a-f have been easily synthesized from dimerâ… (Scheme 1).2. Application of cyclopalladated ferrocenylimine complexes in the synthesis of arylboronate esters.The cyclopalladated ferrocenylimineâ… and its phosphine adductsâ…¡a-f were evaluated in the borylation of aryl halides. Complexâ…¡b exhibited highly catalytic activity for the coupling of aryl and heteroaryl bromides containing various functional groups with low catalyst loading (2 mol%). Aryl and heteroaryl clorides were smoothly converted into the corresponding boronates in the presence of complexâ…¡f (Scheme 2). It was proposed that the borylation catalyzed by adducts of cyclopalladated ferrocenylimineâ…¡a-f proceeded through a classical Pd(0)/Pd(â…¡) cycle based on the Hg poisoning experiments and kinetic studies, and such palladacycle was only a reservoir of the catalytically active Pd(0) species. 3. Application of tricyclohexylphosphine adduct of cyclopalladated ferrocenylimineâ…¡b in the BSC reaction.Phosphine adduct of cyclopalladated ferrocenylimineâ…¡b was highly effective for the BSC reaction of aryl halides and various functionalized biaryls have been obtained in good to excellent yields in "one-pot" (Scheme 3). This procedure tolerated various functional groups, including primary amines, carbonyl, nitriles, etc. In addition, heteroaryl halides could be also employed as substrates.