The stereocontrolled formation of eight- and nine-membered lactones by Cu(I)Cl/2,2’-bipyridine-catalyzed atom transfer cyclization of enantiomerically pure oxygen-substituted Ï-alkenyl di- and trichloroacetates is described. The lactones are formed exclusively via the endo-cyclization mode and generally show a characteristic cis-relationship between the C-5 and C-6 substituents due to a highly stereoselective ring closure and chlorine transfer.
本文描述了通过
铜(I)
氯/
2,2'-联吡啶催化的手性氧取代的β-烯基二
氯和
三氯乙酸酯的原子转移环化反应,实现了八元和九元内酯的立体控制合成。这些内酯的形成完全是通过endo-环化模式,并且由于高度立体选择性的环闭合和
氯转移,通常表现出C-5和C-6取代基之间的特征性顺式关系。