ASYMMETRIC ORGANOCATALYSIS
ASYMMETRIC ORGANOCATALYSIS
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DOI：
10.53879/id.58.10.p0005
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发表时间：
2021-12
期刊：
影响因子：
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通讯作者：
N. Rao
中科院分区：
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作者：
N. Rao
亲爱的读者，在有机化学课程中教我们的两个基本反应是羟醛缩合反应和狄尔斯-阿尔德反应。1872年，法国化学家Charles Wurtz发现了羟醛缩合反应，在酸/碱催化剂存在下，烯醇化物离子与羰基化合物反应形成β-羟基醛或β-羟基酮，通常随后脱水得到共轭烯酮。如果烯醇盐离子和羰基存在于同一分子中，则羟醛缩合反应是分子内的。这是一个非常有用的碳-碳键形成反应。狄尔斯-桤木反应是由德国化学家奥托·狄尔斯（Otto Diels）和他的学生库尔特·桤木（Kurt Alder）在1928年发现的，是共轭二烯和烯烃（所谓的亲二烯体）之间形成不饱和六元环的反应。它被称为环加成反应，因为该反应涉及通过环状过渡态形成环状产物。未催化的狄尔斯-桤木反应通常需要在升高的压力和温度下延长反应时间，并形成副产物，因此使用各种催化剂。狄尔斯-阿尔德反应也有很大的工业相关性，发现者被授予1950年诺贝尔化学奖。羟醛缩合反应和狄尔斯-阿尔德反应通常需要催化剂，基本上是布朗斯台德酸、布朗斯台德碱、刘易斯酸或刘易斯碱。这引发了大卫·麦克米伦博士和本杰明·李斯特博士的思想，他们在美国不同的地方，在20多年前的不同时间，出于不同的原因，最终共同获得了今年的诺贝尔化学奖。
Dear Reader, Two basic reactions that were taught to us in the organic chemistry courses were the aldol condensation reaction and the Diels-Alder reaction. In aldol condensation, discovered by the French chemist Charles Wurtz in 1872, an enolate ion reacts with a carbonyl compound in the presence of an acid/ base catalyst to form a β-hydroxy aldehyde or a β-hydroxy ketone, usually followed by dehydration to give a conjugated enone. If the enolate ion and the carbonyl group are present in the same molecule, then the aldol reaction is intramolecular. It is an extremely useful carbon-carbon bond-forming reaction. The Diels-Alder reaction, discovered in 1928 by the German chemist Otto Diels and his student Kurt Alder, is the reaction between a conjugated diene and an alkene, a so-called dienophile, to form an unsaturated six-membered ring. It is called a cycloaddition reaction, since the reaction involves the formation of a cyclic product via a cyclic transition state. Uncatalysed Diels– Alder reactions usually require extended reaction times at elevated pressures and temperatures with the formation of by-products, hence various catalysts are employed. The Diels-Alder reaction also has great industrial relevance and the discoverers were crowned with the 1950 Nobel Prize in Chemistry. The aldol condensation reaction and the Diels-Alder reaction typically require catalysts, basically Brønsted acids, Brønsted bases, Lewis acids or Lewis bases. This triggered the minds of Dr. David MacMillan and Dr. Benjamin List for different reasons at different locations in USA around not so different times, more than twenty years ago, culminating in their being jointly awarded the Nobel Prize in Chemistry for this year.