Synthesis and application of novel imidazole and 1H-tetrazolic acid containing catalysts in enantioselective organocatalyzed Diels–Alder reactions
摘要:
Herein we report studies on the organocatalytic Diels-Alder reaction using a variety of catalysts capable of activating alpha,beta-unsaturated carbonyl compounds for reactions with dienes. The structurally attractive catalysts 4 and 14 were utilized in the enantioselective organocatalytic Diels-Alder reactions. Catalyst 4 provided the products in fair yields and more importantly in good enantioselectivities of up to 83% ee. Catalyst 14 was synthesized in high yield and was assessed in the enantioselective organocatalytic Diels-Alder reaction. Catalyst 14 proved to be a highly active and selective catalyst providing the products in high yield and high enantioselectivities up to 95% ee. (C) 2009 Elsevier Ltd. All rights reserved.
(Mac‐SILC) in the pores of silica gel with the aid of an ionic liquid – 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide. The heterogenized organocatalyst was utilized for the enantioselectiveDiels–Alder reaction of cyclopentadiene and cinnamaldehyde, recovered by simple filtration and subsequent evacuation, and repeatedly used up to six times in 81% average chemical yield, 87% ee for endo‐
Chemical transformation of substrates using nonmetallic, organic catalyst compositions
申请人:The Regents of the Univerisity of California
公开号:US06369243B1
公开(公告)日:2002-04-09
A method is provided for catalytically transforming a functional group within a first reactant by reaction with a second reactant in the presence of a nonmetallic, organic catalyst composition composed of a heteroatom-containing activator and an acid, or a salt of a heteroatom-containing activator and an acid. Exemplary first reactants are &agr;,&bgr;-unsaturated carbonyl compounds such as &agr;,&bgr;-unsaturated ketones and &agr;,&bgr;-unsaturated aldehydes. The heteroatom of the activator is a Group 15 or Group 16 element such as nitrogen, oxygen, sulfur or phosphorus, and exemplary heteroatom-containing activators are amines. Chiral heteroatom-containing activators can be used to catalyze enantioselective reactions, such that a chiral product is obtained from a chiral or achiral starting material in enantiomerically pure form.
liquid-supported imidazolidinone catalyst I in enantioselectiveDiels–Alderreactions was investigated. The Diels–Alderreactions involving α,β-unsaturated aldehydes and cyclopentadiene proceeded efficiently in the presence of catalyst I to provide the desired products in moderate to good yields with good to excellent enantioselectivities. Especially noteworthy, catalyst I can be recovered and reused
New Strategies for Organic Catalysis: The First Highly Enantioselective Organocatalytic Diels−Alder Reaction
作者:Kateri A. Ahrendt、Christopher J. Borths、David W. C. MacMillan
DOI:10.1021/ja000092s
日期:2000.5.1
employ organic molecules as reaction catalysts, 2 despite the widespread availability of organic chemicals in enantiopure form and the accordant potential for academic, industrial, and economic benefit. Herein, we introduce a newstrategy for organocatalysis that we expect will be amenable to a range of asymmetric transformations. In this context, we document the firsthighlyenantioselective organocatalytic
Recei Ved January 7, 2000 在过去的 30 年中,对映选择性催化已成为探索性有机合成研究中最重要的前沿领域之一。在此期间,有机金属不对称催化剂的开发取得了显着进展,进而提供了丰富的对映选择性氧化、还原、π 键活化和路易斯酸催化过程。1 然而,令人惊讶的是,使用有机分子作为反应催化剂的不对称转化相对较少,2 尽管对映纯形式的有机化学品广泛可用,并且具有相应的学术、工业和经济效益潜力。在此,我们介绍了一种新的有机催化策略,我们预计该策略将适用于一系列不对称转化。在这种情况下,我们记录了第一个高度对映选择性的有机催化 Diels-Alder 反应。3