The reaction of 2-hydroxyglycal esters with alcohols in the presence of N-iodosuccinimide, stereoselective synthesis of α anomers of alkyl 3-deoxyhex-2-enopyranosides and 3,4-dideoxyhex-3-enopyranosid-2-uloses
作者:Oscar Varela、Griselda M. de Fina、Rosa M. de Lederkremer
DOI:10.1016/0008-6215(87)80278-1
日期:1987.9
Abstract Reaction of 2,3,4,6-tetra-O-acetyl-1,5-anhydro- d -arabino-hex-1-enitol (1; 2-hydroxyglucal tetraacetate) with 1.0–1.5 mol of primary secondary, or tertiary alcohols, in the presence of 0.1–1.0 mol of N-iodosuccinimide (NIS) in acetonitrile as solvent, afforded the α anomers of alkyl 3-deoxyhex-2-enopyranosides in very good yields. The reaction proceeded more slowly, and with poorer yields
摘要2,3,4,6-四-O-乙酰基-1,5-脱水-阿拉伯-己糖-1-烯醇(1; 2-羟基葡糖四乙酸酯)与1.0-1.5 mol伯仲,或叔醇在乙腈中存在0.1–1.0 mol N-碘丁二酰亚胺(NIS)作为溶剂时,可以非常好的收率得到烷基3-deoxyhex-2-enopyranosides的α端基异构体。在四苯甲酸酯对应于1的情况下,反应进行得较慢,且收率较差。当1用较高浓度的2-丙醇处理时,反应副产物2-丙基6-O-乙酰基的比例增加产生了-3,4-二脱氧-α-d-甘油-己基-3-烯吡喃糖基-2-ulose(10)。当起始2-羟基乙酸乙酸酯具有lyxo构型时,更容易形成10这样的糖烯酮。因此,一步法制备了两种胆固醇基的α-hex-3-enopyranosid-2-ulose衍生物,并具有良好的收率。在所有这些反应中都观察到了形成α端基异构体的显着立体选择性。