regioselective intermolecular 1,2‐aryl‐aminoalkylation of alkenes by photoredox/nickel dual catalysis is described here. This three‐component conjunctive cross‐coupling is highlighted by its first application of primary alkyl radicals, which were not compatible in previous reports. The readily prepared α‐silyl amines could be transferred to α‐amino radicals by photo‐induced single electron transfer step
Visible-light excitation of iminium ions enables the enantioselective catalytic β-alkylation of enals
作者:Mattia Silvi、Charlie Verrier、Yannick P. Rey、Luca Buzzetti、Paolo Melchiorre
DOI:10.1038/nchem.2748
日期:2017.9
organisms. Herein we demonstrate that the direct excitation of chiral iminium ions can unlock unconventional reaction pathways, enablingenantioselective catalytic photochemical β-alkylations of enals that cannot be realized via thermal activation. The chemistry uses readily available alkyl silanes, which are recalcitrant to classical conjugateadditions, and occurs under illumination by visible-light-emitting
desilylative and decarboxylative additions, allylations, and heteroarylations in the presence of graphitic carbon nitride (g-C3N4) was developed. The procedure has broad scope and provides the desired products in high yields. The heterogeneous nature of the g-C3N4 catalytic system enables easy recovery and recycling as well as the use in multiple runs without loss of activity. The photoredox catalyzed reactions
已开发了在存在石墨化碳氮化物(gC 3 N 4)的情况下,进行甲硅烷基胺和α-氨基酸的光氧化活化的方案,以进行脱甲硅基和脱羧的加成,烯丙基化和杂芳基化。该方法具有广泛的范围,并以高收率提供了所需的产品。gC 3 N 4催化系统的非均质性质使其易于回收和循环利用,并且可以多次使用而不会损失活性。光氧化还原催化的反应也可以以连续的光流方式进行并按比例放大至克级。因此,稳定且容易获得的聚合物gC 3 N 4 提供了均相光敏剂的替代品,用于生成有价值的自由基中间体,用于合成和催化。
Visible-light-mediated addition of α-aminoalkyl radicals generated from α-silylamines to α,β-unsaturated carbonyl compounds
Visible-light-mediated addition of alpha-aminoalkyl radicals generated from alpha-silylamines to alpha,beta-unsaturated carbonylcompounds using a photoredox catalyst is developed. We also succeeded in the isolation of a silyl enol ether as a primary product of the photochemical reaction.