Nickel-catalysed electrochemical carboxylation of allylic acetates and carbonates
摘要:
The electrochemical carboxylation of a series of allylic acetates and carbonates was carried out in the presence of CO(2) under atmospheric pressure, with a catalytic amount of nickel-bipyridine complex, to afford the corresponding beta,gamma-unsaturated carboxylic acids. In the absence of nickel catalyst, alcohols were obtained. (C) 2011 Elsevier Ltd. All rights reserved.
Ti/Pd Bimetallic Systems for the Efficient Allylation of Carbonyl Compounds and Homocoupling Reactions
作者:Alba Millán、Araceli G. Campaña、Btissam Bazdi、Delia Miguel、Luis Álvarez de Cienfuegos、Antonio M. Echavarren、Juan M. Cuerva
DOI:10.1002/chem.201003315
日期:2011.3.28
The allylation, crotylation and prenylation of aldehydes and ketones with stable and easily handled allylic carbonates is promoted by a Ti/Pd catalytic system. This Ti/Pd bimetallic system is especially convenient for the allylation of ketones, which are infrequent substrates in other related protocols, and can be carried out intramolecularly to yield five‐ and six‐membered cyclic products with good
Ti / Pd催化体系可促进醛和酮与稳定且易于处理的烯丙基碳酸酯的烯丙基化,丁酰化和烯丙基化。这种Ti / Pd双金属体系特别适合于酮的烯丙基化,酮是其他相关规程中不常见的底物,并且可以在分子内进行生产,从而产生具有良好立体选择性的五元和六元环状产物。此外,Ti / Pd介导的还原反应和Würtz型二聚反应可以很容易地从碳酸烯丙酯和羧酸酯中进行。
γ-Selective allylic substitution reaction with Grignard reagents catalyzed by copper N -heterocyclic carbene complexes and its application to enantioselective synthesis
The reaction of allylic compounds with alkyl Grignard reagents in the presence of a catalytic amount of copper N-heterocyclic carbene (NHC) complexes proceeded predominantly in an SN2′ reaction pathway to give γ-substituted product in excellent yield. The method was applied to asymmetric reaction by using optically active NHC ligands.
Stereoselective palladium-catalyzed allylic alkylations of peptideamide enolates
作者:Swarup Datta、Uli Kazmaier
DOI:10.1039/c0ob00628a
日期:——
Pd-catalyzed allylations are an excellent tool for stereoselectivepeptide modifications, being clearly superior to normal alkylations. The reactions proceed not only in high yield, but also high regio- and diastereoselectivities, and trans-products are formed exclusively. Therefore, this is a powerful synthetic tool for natural product and drug synthesis.
Palladium(O)-catalyzed alkylation of various allylic carbonates by aromatic thiols allowed the easy preparation of various allylic aryl sulphides in quite good yields. The reaction was regioselective with substitution at the less hindered side of the π-allyl system whatever the temperature of the reaction, and was diastereoselective with net retention of configuration.