自由基对不对称烯烃加成反应的根本的和重要的问题之一,是定位或取向问题.根据我们过去的观点和工作,特别是根据Tedder近十几年来取得的结果,自由基对偏氟乙烯的加成反应是双向的,其定位选择性随自由基而异.但1975年Kochi报道叔丁氧基自由基只加到偏氟乙烯的CF_2端,并认为其结果显示目前的理论是不足的.这问题成为近年来自由基加成反应中的一个“疙瘩”. Radicals One of the fundamental and important issues in the asymmetric addition of olefins is orientation or orientation. Based on our past observations and work, especially on the basis of the results of Tedder over the past decade or so, The addition reaction of ethylene is bi-directional and its selectivity varies with free radicals, but in 1975 Kochi reported that t-butoxy radicals were added only to the CF2 end of vinylidene fluoride and concluded that the results show that the current theory is inadequate This problem has become a “knot” in the radical addition reaction in recent years.