Chromium-pillared clay as a catalyst for benzylic oxidation and oxidative deprotection of benzyl ethers and benzylamines: a simple and convenient procedure
摘要:
A mild and efficient method for benzylic oxidation of arylmethylenes to the corresponding carbonyl compounds in good yields is described using a catalytic amount of chromium-pillared montmorillonite and equimolar quantities of tert-butyl hydroperoxide. The method is very selective toward monocarbonyl compounds of the substrates prone to form dicarbonyl compounds. The present heterogeneous catalyst is inert toward the branched hydrocarbons and has been put to practice to obtain p-isobutylacetophenone selectively from p-isobutylethylbenzene. Further, the method is extended successfully to the oxidative debenzylation reactions for the first time. A striking feature of the oxidative deprotection with the present method is the deprotection of a benzyl group from the substrates having an alkyne moiety.
Biocatalytic <i>N</i>-Alkylation of Amines Using Either Primary Alcohols or Carboxylic Acids via Reductive Aminase Cascades
作者:Jeremy I. Ramsden、Rachel S. Heath、Sasha R. Derrington、Sarah L. Montgomery、Juan Mangas-Sanchez、Keith R. Mulholland、Nicholas J. Turner
DOI:10.1021/jacs.8b11561
日期:2019.1.23
The alkylation of amines with either alcohols or carboxylic acids represents a mild and safe alternative to the use of genotoxic alkyl halides and sulfonate esters. Here we report two complementary one-pot systems in which the reductive aminase (RedAm) from Aspergillus oryzae is combined with either (i) a 1° alcohol/alcohol oxidase (AO) or (ii) carboxylic acid/carboxylic acid reductase (CAR) to affect
Amination of Alcohols Catalyzed by Copper-Aluminium Hydrotalcite: A Green Synthesis of Amines
作者:Pravin R. Likhar、Racha Arundhathi、Mannepalli Lakshmi Kantam、Parvathaneni Sai Prathima
DOI:10.1002/ejoc.200900628
日期:2009.11
Copper-aluminiumhydrotalcite (CuAl-HT)/K2CO3 has been employed in the activation of various benzyl alcohols with benzylamines to afford the corresponding amines in good to high yields. Experimentation showed that the reaction takes place through sequential transformations: the oxidation of alcohols into carbonyl compounds, imine formation between amines and carbonyl compounds, and then reduction ofimines
Highly economical and direct amination of sp<sup>3</sup> carbon using low-cost nickel pincer catalyst
作者:Andrew Brandt、Ambar B. RanguMagar、Peter Szwedo、Hunter A. Wayland、Charlette M. Parnell、Pradip Munshi、Anindya Ghosh
DOI:10.1039/d0ra09639c
日期:——
first time, we report the use of an amide-based nickel pincer catalyst (1) for direct alkylation of amines viaactivation of sp3 C-H bonds. The reaction was accomplished using a 0.2 mol% catalyst and no additional activatingagents other than the base. Upon optimization, it was determined that the ideal reaction conditions involved solvent dimethyl sulfoxide at 110 °C for 3 h. The catalyst demonstrated
Direct and indirect reductive amination of aldehydes and ketones with solid acid-activated sodium borohydride under solvent-free conditions
作者:Byung Tae Cho、Sang Kyu Kang
DOI:10.1016/j.tet.2005.04.039
日期:2005.6
A simple and convenient procedure for reductive amination of aldehydes and ketonesusingsodiumborohydride activated by boric acid, p-toluenesulfonic acid monohydrate or benzoic acid as reducing agent under solvent-free conditions is described.
<i>cine</i>-Silylative Ring-Opening of α-Methyl Azacycles Enabled by the Silylium-Induced C–N Bond Cleavage
作者:Jianbo Zhang、Sukbok Chang
DOI:10.1021/jacs.0c05241
日期:2020.7.22
exo-dehydrogenation of alicyclic amine, (ii) hydrosilylation of resultant enamine, (iii) silylium-induced cis-β-amino elimination to open the ring skeleton, and (iv) hydrosilylation of terminal olefin. The present borane catalysis also works efficiently for the C-Nbondcleavage of acyclic tertiary amines. On the basis of experimental and computational studies, the silicon atom was elucidated to play a pivotal