3-O-isopropylidene-d-glyceraldehyde nitrone (Mannich-type reaction) can be stereocontrolled to give 2S,3S,4S and 2R,3R,4S adducts as major compounds, depending on whether the reaction is activated with zinc(II) triflate or tin(IV) chloride, respectively. The corresponding major adducts were used for preparing diastereomeric polyhydroxy-β-aminoesters that were further converted into suitable orthogonally
2-甲
硅烷氧基silylketene
缩醛的添加ñ -苄基-2,3- ö异亚丙基d
甘油醛硝酮(曼尼希型反应)可以立体控制,得到2-小号,3小号,4小号和2 - [R,3 R,4 S加合物为主要化合物,取决于反应分别用
三氟甲磺酸锌(II)或
氯化锡(IV)活化。相应的主要加合物用于制备非对映体的多羟基-β-
氨基酯,将其进一步转化为合适的正交保护的对映体d-和l-赤型-
鞘氨醇。