A New Type of Donor-Acceptor Cyclopropane Reactivity: The Generation of Formal 1,2- and 1,4-Dipoles
作者:Roman A. Novikov、Anna V. Tarasova、Victor A. Korolev、Vladimir P. Timofeev、Yury V. Tomilov
DOI:10.1002/anie.201306186
日期:2014.3.17
A new type of donor–acceptor cyclopropane reactivity has been discovered. On treatment with anhydrous GaCl3, they react as sources of even‐numbered 1,2‐ and 1,4‐dipoles instead of the classical odd‐numbered 1,3‐dipoles due to migration of positive charge from the benzyl center. This type of reactivity has been demonstrated for new reactions, namely, cyclodimerizations of donor–acceptor cyclopropanes
已经发现了一种新型的供体-受体环丙烷反应性。用无水GaCl 3处理,由于正电荷从苄基中心迁移,它们作为偶数1,2和1,4偶极子而不是经典的奇数1,3偶极子发生反应。这种类型的反应性已被证明可用于新的反应,即供体-受体环丙烷的环二聚反应以[2 + 2]-,[3 + 2]-,[4 + 2]-,[5 + 2]-, [4 + 3]-和[5 + 4]-环。2-芳基环丙烷-1,1-二羧酸酯的[4 + 2]环化反应可制得多取代的2-芳基四氢萘,这是一种制备型化合物,具有极高的区域和非对映选择性,并具有很高的收率。还开发了供体-受体环丙烷选择性杂合的策略。研究了发现的涉及形成相对稳定的1,2-内酯中间体的反应机理。