Donor-substituted furans and 1,2-bis(trifluoromethyl)ethylene-1,2-dicarbonitrile: A novel rearrangement and its steric course
作者:Gonzalo Urrutia-Desmaison、Grzegorz Mloston、Rolf Huisgen
DOI:10.1016/s0040-4039(00)73297-7
日期:1994.7
Opening of the furan ring and concomitant closure of a cyclopropane ring was observed in the reaction of 2-methoxy- and 2-p-tolyloxyfuran with 2,3-bis(trifluoromethyl)fumaronitrile (trans-BTE). Electrophilic 5-attack gives rise to a zwitterion which can rotate about the acceptor bond, dissociate to reactants, or furnish diastereoisomeric cis-3-cyclopropylacrylates. In the presence of pyridine, 1,3-prototropy
在2-甲氧基-和2-对甲苯甲氧基呋喃与2,3-双(三氟甲基)富马腈(反式-BTE)的反应中观察到呋喃环的打开和环丙烷环的同时闭合。亲电子性的5-攻击产生两性离子,其可绕受体键旋转,离解成反应物或提供非对映异构体顺式-3-环丙基丙烯酸酯。在吡啶的存在下,1,3-原生质将两性离子转化为5-取代的呋喃。