Medium-sized lactones (eight- to eleven-membered rings) are efficiently formed by Cu(bpy)Cl catalyzed cyclization of various alkenyl di- and trichloroacetates at temperatures between 80 and 190°C in 1,2-dichloroethane or benzene as solvents. The mechanism of the alkene addition reaction is best understood as a chlorine atom transfer process through radical type intermediates. Exclusive endo-cyclization
中性内酯(8至11元环)是通过Cu(bpy)Cl在
1,2-二氯乙烷或苯中的80-190°C温度下催化各种烯基二-和
三氯乙酸酯的环化反应有效形成的。最好将烯烃加成反应的机理理解为通过自由基型中间体进行的
氯原子转移过程。独家内-cyclization在所有病例中观察到。十元和十一元内酯只能通过“刚性链”方法访问,在该方法中,
炔烃或烯烃官能团被纳入连接反应中心的链中,从而降低了分子的柔韧性。