Preliminary investigations on novel camphor-derived chiral sulfones: completely stereoselective formation of tricyclic β-hydroxy sulfones from 8- and 10-functionalized camphor derivatives
作者:Frank W. Lewis、Thomas C. McCabe、David H. Grayson
DOI:10.1016/j.tet.2011.07.081
日期:2011.9
β-hydroxy sulfones whose relative configurations were determined by X-ray crystallography. Tricyclic sulfones 23 and 24 underwent both β-elimination and retro-aldol reactions on further exposure to base. Reduction of the carbonyl group of the C-10 substituted sulfones afforded exo-configured isobornyl sulfones with high stereoselectivity. Reaction of the lithiated isobornyl benzyl sulfone 32 with benzaldehyde
合成了一些樟脑衍生的手性烯丙基和苄基砜,其中磺酰基位于(+)-樟脑的C-10,C-9或C-8甲基上。C-9和C-8取代的砜是通过双环樟脑骨架的Wagner-Meerwein重排获得的。用LDA处理后,C-10和C-8取代的砜以完全的立体选择性环化,得到三环β-羟基砜,其相对构型通过X射线晶体学测定。当进一步暴露于碱中时,三环砜23和24均经过β消除和逆醛醇缩合反应。C-10取代的砜的羰基还原得到exo立体选择性高的异戊烯基砜。锂化的异冰片基苄基砜32与苯甲醛的反应生成了所有四种可能的产物非对映异构体,其中三种通过色谱法纯分离出。尝试对这些非对映异构体进行磺酰基化反应无法生成所需的旋光性高苄基醇,但在模型非手性系列化合物中,相同的磺酰基碳负离子捕获/脱磺酰基序列是成功的。