Diastereoselective Control of Intramolecular Aza-Michael Reactions Using Achiral Catalysts
摘要:
An intramolecular aza-Michael reaction with a Cbz carbamate and an enone is reported to result in 3,5-disubstituted nitrogen-containing heterocycles. Either cis or trans isomers were obtained selectively using chiral substrates and an achiral Pd (II) complex or strong Bronsted acid catalysis. A range of substrates undergoes these selective transformations. Functionalization of the resulting products yielding bicyclic heterocycles is also demonstrated.
Nickel-Catalyzed Isomerization/Allylic Cyanation of Alkenyl Alcohols
作者:Ying Ding、Jinguo Long、Feilong Sun、Xianjie Fang
DOI:10.1021/acs.orglett.1c02143
日期:2021.8.6
Herein reported is a nickel-catalyzed isomerization/allylic cyanation of alkenyl alcohols, which complements current methods for the allylic substitution reactions. The specific diphosphite ligand and methanol as the solvent are crucial for the success for this transformation. A gram-scale regioconvergent experiment and formal synthesis of quebrachamine demonstrate the high potential of this methodology
We, herein, report on the bromocyanation of styrene derivatives with cyanogen bromide in the presence of tris(pentafluorophenyl)borane which functions as a Lewis acid catalyst that can effectively activate cyanogen bromide. This reaction proceeds through a stereospecific syn-addition. The protocol is operationally simple and provides practical access to β-bromonitriles.
Herein, we report a direct method for the synthesis of α-imidoketones and α-azolylketones via hypoiodite-catalyzed oxidative α-C−N coupling of ketones with the corresponding imides and azoles, respectively. The use of inorganic base additives such as cesium carbonate in the presence of 18-crown-6 as a phase transfer catalyst was crucial to induce high reactivity. Control experiments revealed that the
Nucleophilic character of alkyl radicals. 18. Absolute rate constants for the addition of primary alkyl radicals to conjugated olefins and 1,4-benzoquinone
作者:A. Citterio、A. Arnoldi、F. Minisci
DOI:10.1021/jo01329a017
日期:1979.7
Diastereoselective Control of Intramolecular Aza-Michael Reactions Using Achiral Catalysts
作者:Cheng Zhong、Yikai Wang、Alvin W. Hung、Stuart L. Schreiber、Damian W. Young
DOI:10.1021/ol202276h
日期:2011.10.21
An intramolecular aza-Michael reaction with a Cbz carbamate and an enone is reported to result in 3,5-disubstituted nitrogen-containing heterocycles. Either cis or trans isomers were obtained selectively using chiral substrates and an achiral Pd (II) complex or strong Bronsted acid catalysis. A range of substrates undergoes these selective transformations. Functionalization of the resulting products yielding bicyclic heterocycles is also demonstrated.