Straightforward Synthesis of (1→2)-Linked Pseudo Aza-<i>C</i>-disaccharides by the Novel Cycloaddition of Enantiopure Cyclic Nitrones to Glycals
作者:Francesca Cardona、Silvia Valenza、Sylviane Picasso、Andrea Goti、Alberto Brandi
DOI:10.1021/jo980809i
日期:1998.10.1
The novel, highly stereoselective, intermolecular cycloaddition reaction of enantiopure cyclic nitrones 8 to 1,2-glycals 9 opens the way to a straightforward synthesis of a broad class of new (1-->2)-linked pseudo aza-C-disaccharides 6, suitable substrates for selective inhibition of glycosidase enzymes. The cycloadditions occur with high stereocontrol, displaying preferential interaction between the
对映纯环硝酮8与1,2-糖9的新颖的高度立体选择性分子间环加成反应为直接合成各种新的(1-> 2)连接的伪aza-C-二糖6开辟了道路,是选择性抑制糖苷酶的合适底物。环加成反应在高度立体控制下发生,显示出糖基的底面和抗C-3取代基的硝酮表面之间的优先相互作用,试剂以exo方式接近。环加成产生三环异恶唑烷7,其代表对水解条件稳定的非还原性假氮杂-C-二糖。通过羟基的连续脱保护和异恶唑烷开环获得目标伪氮杂二糖6。