从11-木糖的11个合成步骤中描述了粟精胺的非对映选择性合成。1-木糖,烯丙胺和(E)-苯乙烯硼酸之间的硼酸-曼尼希反应产生目标分子中C-6,C-7,C-8和C-8a具有所需构型的四羟基胺。一种新颖的吡咯并[1,2 - c ]恶唑-3-one前体被用来控制(VIII)催化的顺二羟基化(DH)反应中的π面非对映选择性。然后,所得到的二醇的环状硫酸酯衍生物的区域选择性开环以正确的构型确保了粟精胺的C-1羟基。然后,Mitsunobu环化提供了Di- O-苄基粟精胺和最终的最终目标生物碱。
A Flexible Approach to Azasugars: Asymmetric Total Syntheses of (+)-Castanospermine, (+)-7-Deoxy-6-<i>epi</i>-castanospermine, and (+)-1-<i>epi</i>-Castanospermine
The asymmetric total synthesis of natural azasugars (+)‐castanospermine, (+)‐7‐deoxy‐6‐epi‐castanospermine, and synthetic (+)‐1‐epi‐castanospermine has been accomplished in nine to ten steps from a common chiral building block (S)‐8. The method features a powerful chiral relay strategy consisting of a highly diastereoselective vinylogous Mukaiyama‐type reaction with either chiral or achiral aldehydes
作者:Theeraphan Machan、Andrew S. Davis、Boonsom Liawruangrath、Stephen G. Pyne
DOI:10.1016/j.tet.2008.01.073
日期:2008.3
The diastereoselective synthesis of castanospermine is described in 11 synthetic steps from l-xylose. The borono-Mannich reaction between l-xylose, allylamine, and (E)-styrene boronic acid gives a tetrahydroxy amine with the desired configurations for C-6, C-7, C-8, and C-8a in the target molecule. A novel pyrrolo[1,2-c]oxazol-3-one precursor was employed to allow for the control of π-facial diastereoselectivity
从11-木糖的11个合成步骤中描述了粟精胺的非对映选择性合成。1-木糖,烯丙胺和(E)-苯乙烯硼酸之间的硼酸-曼尼希反应产生目标分子中C-6,C-7,C-8和C-8a具有所需构型的四羟基胺。一种新颖的吡咯并[1,2 - c ]恶唑-3-one前体被用来控制(VIII)催化的顺二羟基化(DH)反应中的π面非对映选择性。然后,所得到的二醇的环状硫酸酯衍生物的区域选择性开环以正确的构型确保了粟精胺的C-1羟基。然后,Mitsunobu环化提供了Di- O-苄基粟精胺和最终的最终目标生物碱。