Cyclopentene and cyclohexene annulation via copper-catalyzed conjugate addition of acetal-containing Grignard reagents
Cyclopentene and cyclohexene annulation via copper-catalyzed conjugate addition of acetal-containing Grignard reagents
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DOI：
10.1021/jo00147a001
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发表时间：
1982-12
影响因子：
3.6
通讯作者：
Swati A. Bal;A. Marfat;P. Helquist
中科院分区：
文献类型：
--
作者：
Swati A. Bal;A. Marfat;P. Helquist
衍生自2-（2-溴乙基）-和2-（3-氯丙基）-1，3-二氧戊环的格氏试剂2在催化量的亚铜盐存在下与许多α-不饱和酮进行共轭加成.在用盐酸处理时，所得酮缩醛经历顺序水解、分子内羟醛缩合和脱水，得到环戊烯和环己烯成环产物。整个系列的反应，从共轭加成开始，可以作为一个烧瓶实验进行，直接形成环化产物。格利雅试剂还可以用环氧化物进行烷基化或用酰氯进行酰化，得到中间体，这些中间体可以通过与上述相关的途径转化为环状产物。碳环化合物，特别是五元环和六元环的构建是许多合成有机化学的中心主题，因为无数的天然产物和工业上重要的化合物都含有这些环系统。已经开发的用于合成这些化合物的许多方法已经成为几个综述的主题。1
The Grignard reagents 2 derived from 2-(2-bromoethyl)-and 2-(3-chloropropyl)-l, 3-dioxolane undergo conjugate addition to a number of, ß-unsaturated ketones in the presence of a catalytic amount of a cuprous salt. The resulting keto acetals, upon treatment with hydrochloric acid, undergo sequential hydrolysis, intramolecular aldol condensation, and dehydration to give cyclopentene and cyclohexene annulation products. The entire series of reactions, startingwith the conjugate addition, may be performed as a one-flask experiment leading to direct formation of the cyclization products. The Grignard reagents may also be alkylated with epoxides or acylated with an acid chloride to give intermediates that may be converted into cyclic products bypathways related to those above.The construction of carbocyclic compounds, and five-and six-membered rings in particular, is a central theme of much of synthetic organic chemistry because of the countless numbers of natural products and industrially important compounds that contain these ring systems. The numerous methods that have been developed for the synthesis of these compounds have been the subjectof several reviews. 1