Palladium-Catalyzed Decarboxylative Asymmetric Allylic Alkylation of β-ketoesters: An Unusual Counterion Effect
作者:Barry M. Trost、Benjamin Schäffner、Maksim Osipov、Donna A. A. Wilton
DOI:10.1002/anie.201007803
日期:2011.4.4
allyl chloroformate and their β‐ketoesters by using the same catalyst system (see scheme; dba=dibenzylideneacetone, 1,2‐DCE=1,2‐dichloroethane, THF=tetrahydrofuran). The details of this remarkable effect were investigated by performing scavenging experiments and a variety of substrates were successfully used in the procedure.
A highly efficient and regioselective allylation reaction of amines and active methylene compounds directly using allylicalcohols under mild conditions catalyzed by the novel cubane-type sulfido [(Cp*Mo)3(μ3-S)4Pd(η3-allyl)][PF6]2 clusters has been developed. A variety of allylicalcohols and nucleophiles including amines and active methylene compounds are investigated, and in the case of allylic alcohols
The Polymer Incarcerated Method for the Preparation of Highly Active Heterogeneous Palladium Catalysts
作者:Ryo Akiyama、Shū Kobayashi
DOI:10.1021/ja029146j
日期:2003.3.1
incarcerated (PI) method" for preparing a heterogeneouspalladiumcatalyst has been developed. The method is operationally simple, and the Pd catalyst prepared (PI Pd) is highlyactive for hydrogenation, carbon-carbon, and carbon-oxygen bond-forming reactions. Remarkable points are that the activity of PI Pd is higher than that of homogeneous Pd catalysts and that PI Pd is recovered by simple filtration
Tris(4-bromophenyl)aminium Hexachloroantimonate-Mediated Intermolecular C(sp<sup>2</sup>)–C(sp<sup>3</sup>) Free Radical Coupling of Vindoline with β-Ketoesters and Related Compounds
作者:Jiajun Zhang、Srinivas R. Paladugu、Rachel M. Gillard、Anindya Sarkar、Dale L. Boger
DOI:10.1021/jacs.1c10971
日期:2022.1.12
proceeds with generation of a quaternary center bound to the aryl C15 center of vindoline capable of accommodating of the vinblastine C16′ methyl ester and functionalized for subsequent divergent heterocycle introduction. A comprehensive examination of the reaction scope, optimization of subtle reaction parameters, and key insights into the reaction mechanism are described. Contrary to what might be prevailing
六氯锑酸三(4-溴苯基)铵 (BAHA) 介导的文多灵与多种底物(包括 β-酮酯、β-二酮、β-酮醛、β-酮腈、β-酮内酯、β-详细描述了酮内酰胺、β-氰酸酯和丙二腈。 BAHA 促进的分子间 sp 3 /sp 2偶联代表一类特殊的选择性 C-H 官能化反应,可直接形成碳-碳键,并生成与文多灵的芳基 C15 中心结合的四级中心,能够容纳长春花碱 C16' 甲酯并进行官能化以用于随后引入不同的杂环。描述了对反应范围的全面检查、微妙反应参数的优化以及对反应机理的关键见解。与普遍的预期相反,研究表明,合理的机制需要底物烯醇化物(而不是文多林)的初始单电子氧化,以及随后将所得亲电子自由基区域特异性添加到文多林上。因此,除了文多灵的新芳基化反应之外,这些研究还定义了 BAHA 和相关三芳基胺自由基阳离子的许多新的、以前未被认识的应用,这些应用源于它们在非还原和无金属条件。本文示例的那些包括介导稳定的
Asymmetric alkylation of .beta.-keto esters with optically active sulfonium salts