Vicarious nucleophilic substitution of hydrogen (VNS) in 1,4-naphthoquinone derivatives—competition between VNS and vinylic nucleophilic substitution (SNV)
作者:Mieczysław Mąkosza、Shamil Nizamov
DOI:10.1016/s0040-4020(01)00962-0
日期:2001.11
Carbanions of dimethyl chloromalonate, ethyl 2-chloroacetoacetate and dimethyl malonate react with naphthoquinone derivatives mainly via vicarious nucleophilic substitution or oxidative nucleophilic substitution of hydrogen processes. These reactions in 2-halo substituted naphthoquinones are generally faster processes than vinylic nucleophilic substitution of halogen (SNV). Introduction of one Cl substituent
氯丙二酸二甲酯,2-氯乙酰乙酸乙酯和丙二酸二甲酯的碳负离子主要通过氢过程的替代性亲核取代或氧化亲核取代与萘醌衍生物反应。在2-卤代萘醌,这些反应比卤素的乙烯基亲核取代(S通常较快的过程中Ñ V)。将一个Cl取代基引入1,4-萘醌的2-位大大提高了其亲电子活性,导致碳氢原子在氢占据的位置更快地加成。另一方面,向2,3-二氯-1,4-萘醌中添加碳负离子的速度比向1,4-萘醌中添加碳负离子的速度慢。