New dimerization and cascade oligomerization reactions of dimethyl 2-phenylcyclopropan-1,1-dicarboxylate catalyzed by Lewis acids
作者:Roman A. Novikov、Victor A. Korolev、Vladimir P. Timofeev、Yury V. Tomilov
DOI:10.1016/j.tetlet.2011.07.001
日期:2011.9
New routes to transform donor–acceptor cyclopropanes in the presence of Lewis acids have been found. The reaction of dimethyl 2-phenylcyclopropan-1,1-dicarboxylate, a typical representative of this class of compounds, with an equimolar amount of anhydrous GaCl3 gives, depending on the reaction time, (2-phenylethylidene)malonate or styrylmalonate after hydrolysis, whereas in the presence of 15–20 mol %
发现了在路易斯酸存在下转化供体-受体环丙烷的新途径。这类化合物的典型代表-2-苯基环丙烷-1,1-二羧酸二甲酯与等摩尔量的无水GaCl 3反应,根据反应时间,水解后生成(2-苯基亚乙基)丙二酸酯或苯乙烯基丙二酸酯。在存在15–20 mol%GaCl 3的情况下,起始环丙烷进行二聚化,生成3,4-二苯基环戊烷-1,1-二羧酸的丙二酸酯衍生物。在GaCl 3 ·THF络合物的存在下,相同的环丙烷以高收率生成取代的4-苯基四氢-2,2-二羧酸酯,而在SnCl 4的存在下·THF可得到上述指定的二聚体以及链低聚产物,其程度可通过改变溶液中起始环丙烷的浓度来控制。