Enantiomeric synthesis of polyhydroxylated indolizidine analogues related to castanospermine: 1-deoxy-7-epicastanospermine and 1,7-dideoxy-7-fluorocastanospermine
作者:C.-Kuan Lee、K.Y. Sim、Jun Zhu
DOI:10.1016/s0040-4020(01)86601-1
日期:1992.9
(6S,7S,8R,8aR)-6,7,8-Trihydroxyindolizidine (1) and its (7R)-deoxyfluoro analogue (2) was synthesised from 5,8-benzyloxycarbonylimino-5,6,7,8-tetradeoxy-1,2-O-isopropylidene-alpha-D-gluco-octose (3). The key step is an oxidation-reduction sequence. Introduction of a fluoro substituent at C-3 (6) was readily effected by displacement of the 3-trifluoromethanesulfonyl (triflate) group with tris-(dimethylamino)-sulfonium-difluorotrimethylsilicate (TASF).
(6S,7S,8R,8aR)-6,7,8-三羟基吲哚嗪啶(1)及其(7R)-去氧氟类似物(2)是由5,8-苯甲氧基亚氨基-5,6,7,8-四去氧-1,2-O-异丙基甲基-C-α-D-葡萄-八糖(3)合成的。关键步骤是氧化还原序列。在C-3位引入氟代基团(6)是通过用三甲基甲硅烷二氟化物甲基硫酸酯(TASF)取代3-三氟甲基磺酸酯(triflate)基团来实现的。