9-(Diphenylphosphino)anthracene-based phosphapalladacycle catalyzed conjugate addition of arylboronic acids to electron-deficient alkenes
作者:Minori Shimizu、Tetsuya Yamamoto
DOI:10.1016/j.tetlet.2020.152257
日期:2020.8
9-(Diphenylphosphino)anthracene-based phosphapalladacycle catalyzed conjugateaddition of arylboronic acids to electron-deficient alkenes such asα,β-unsaturated ketones, esters, nitrile and nitroalkenes gave corresponding β-arylated alkanes in good yields and achieved TON up to 700.
Heterogeneous catalytic 1,4-addition of arylmagnesium compounds to chalcones
作者:Kinga Juhász、Zoltán Hell
DOI:10.1016/j.tetlet.2018.07.016
日期:2018.8
Copper(II) on a 4 Å molecular sieve support catalyses the chemoselective addition of alkyl- and arylmagnesiumhalides to chalcones. Only the 1,4-addition products were obtained in high yields.
Copper complexes of phosphoramidites efficiently catalyzed asymmetricaddition of arylboron reagents to acyclic enones. Importantly, rare 1,4-insertion of arylcopper(I) was identified which led directly to O-bound copper enolates. The new mechanism is fundamentally different from classical oxidative addition/reductive elimination of organocopper(I) on enones.
亚磷酰胺的铜配合物有效地催化芳基硼试剂向无环烯酮的不对称加成。重要的是,鉴定了稀有的芳基铜(I)的 1,4-插入,这直接导致了与 O 结合的铜烯醇化物。新机制与传统的有机铜(I)在烯酮上的氧化加成/还原消除有着根本的不同。
Uncatalyzed conjugate addition of organozinc halides to enones in DME: a combined experimental/computational study on the role of the solvent and the reaction mechanism
calculations, prompted by the experimental aggregation study, revealed an unexpected reactionmechanism, where the coordinating capabilities of DME stabilize a transition state involving two organozinc moieties, lowering the activation energy of the reaction with respect to that seen for THF, enough to explain the fast and quantitative reactions observed experimentally and the different behaviors of
Conjugateaddition of α,β-unsaturated ketones with arylzinc species that form in situ from diethylzinc and a series of arylboronic acids by boron-zinc exchange reactions were investigated. 1,4-Addition products were formed in yields of 34-93%.