Silylmethylene radical cyclization. A stereoselective approach to branched sugars
作者:Valérie Pedretti、Jean-Maurice Mallet、Pierre Sinaÿ
DOI:10.1016/0008-6215(83)85005-8
日期:1993.6
oxidation of the sila cycle. Ethyl 6- O -benzyl-2,3-dideoxy-α- d - threo -hex-2-enopyranoside and benzyl 2,6-di- O -benzyl-α- l - threo -hex-4-enopyranoside were similarly transformed into, respectively, ethyl 6- O -benzyl-2,3-dideoxy-3- C -(hydroxymethyl)-α- d - lyxo -hex-2-enopyranoside (50%), and benzyl 2,6-di- O -benzyl-4-deoxy-4- C -(hydroxymethyl)-β- d -galactopyranoside (71%).
摘要将乙基6-O-苄基-2,3-二脱氧-α-d-赤型-己基-2-烯吡喃糖苷(2)分三步以73%的总收率转化为乙基6-O-苄基-2 ,3-二脱氧-3-C-(羟甲基)-α-d-核糖-十六烷基-2-烯吡喃糖苷。该转化过程包括用(溴甲基)氯二甲基硅烷将2进行甲硅烷基化,以及应用Nishiyama-Stork自由基环化反应,然后对sila循环进行Tamao氧化反应。类似地转化了乙基6-O-苄基-2,3-二脱氧-α-d-苏-己-2--2-吡喃糖苷和苄基2,6-二-O-苄基-α-1-苏-己六-4-烯吡喃糖苷分别转化为乙基6-O-苄基-2,3-二脱氧-3-C-(羟甲基)-α-d-lyxo-hex-2-enopyranoside(50%)和苄基2,6-di-O -苄基-4-脱氧-4-C-(羟甲基)-β-d-吡喃半乳糖苷(71%)。