作者:Alphert E. Christina、Daan van der Es、Jasper Dinkelaar、Hermen S. Overkleeft、Gijsbert A. van der Marel、Jeroen D. C. Codée
DOI:10.1039/c2cc17623h
日期:——
Upon condensation of 6-thio-6-deoxy-mannosyl donors 1,2-cis products are obtained with a high degree of stereoselectivity. Subsequent reductive removal of the 6-thio functionality gives 1,2-cisrhamnosides. The 1,2-cis-selectivity can be rationalized with a product forming 3H4-oxocarbenium, which is in equilibrium with a bridged sulfonium intermediate.
当6-硫-6-脱氧甘露糖供体进行缩合时,会高度立体选择性地得到1,2-顺式产物。随后通过还原性移除6-硫功能基团,生成1,2-顺式鼠李糖苷。1,2-顺式选择性可通过生成产物形式的3H4-氧碳鎓离子来合理化,这一离子与桥连的硫鎓中间体处于平衡状态。