Enantioselective rhodium/ruthenium photoredox catalysis en route to chiral 1,2-aminoalcohols
作者:Jiajia Ma、Klaus Harms、Eric Meggers
DOI:10.1039/c6cc04397f
日期:——
A rhodium-based chiral Lewis acid catalyst combined with [Ru(bpy)3](PF6)2 as photoredox sensitizer allows for the visible-light-activated redox coupling of [small alpha]-silylamines with 2-acyl imidazoles to afford, after desilylation, 1,2-amino-alcohols in yields...
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。
Enantioselective Conjugate Additions of α-Amino Radicals via Cooperative Photoredox and Lewis Acid Catalysis
作者:Laura Ruiz Espelt、Iain S. McPherson、Eric M. Wiensch、Tehshik P. Yoon
DOI:10.1021/ja512746q
日期:2015.2.25
We report the highly enantioselective addition of photogenerated α-amino radicals to Michael acceptors. This method features a dual-catalyst protocol that combines transition metal photoredox catalysis with chiral Lewisacidcatalysis. The combination of these two powerful modes of catalysis provides an effective, general strategy to generate and control the reactivity of photogenerated reactive intermediates
The preparation of N-containing α,β-unsaturated carboxylate derivatives from α-silylamine and Baylis-Hillmanadducts under visible light irradiation was reported. The formation of α-aminoalkyl radical is regioselective compared with the previous reports. The reaction was successfully performed without additional additives under mild conditions.
high‐yielding addition reaction (19 examples, 66–99 % yield) with various N‐(trimethylsilyl)methyl‐substituted amines upon irradiation with visiblelight and catalysis by a metal complex. If the alkylidene substituent is non‐symmetric and if the reaction is performed in the presence of a chiral hydrogen‐bonding template, products are obtained with significant enantioselectivity (58–72 % ee) as a mixture