4-<i>O</i>-Benzyl-2,3-<i>O</i>-isopropylidene-D-erythrose and -D-threose from 2,3-<i>O</i>-Isopropylidene-D-glyceraldehyde via Thiazole Intermediates. Synthesis of 2-Deoxykanosamine
作者:Alessandro Dondoni、Pedro Merino
DOI:10.1055/s-1992-34166
日期:——
The adduct derived from 2,3-O-isopropylidene-D-glyceraldehyde and 2-(trimethylsilyl)thiazole is readily converted into the title D-erythrose (50% overal yield) by selective protection of the hydroxy groups and cleavage of the thiazole ring; the D-threose derivative is obtained from the former by base-catalyzed epimerization at C-2. Wittig olefination of the D-erythrose derivative followed by Michael addition of benzylamine and aldehyde liberation from the thiazole ring leads to the amino sugar 2-deoxykanosamine (methyl 6-O-benzyl-3-benzylamino-2,3-dideoxy-α -D-arabinopyranoside) in 50% overall yield.
由 2,3-O-异亚丙基-D-甘油醛和 2-(三甲基硅基)噻唑生成的加合物很容易通过羟基的选择性保护和噻唑环的裂解转化成标题中的 D-赤藓糖(总收率为 50%);D-苏糖衍生物则是由前者通过碱催化 C-2 处的缩合反应生成的。D- 赤藓糖衍生物经 Wittig 烯化后,再与苄胺进行迈克尔加成,并从噻唑环中释放出醛,从而得到氨基糖 2-脱氧卡诺萨明(甲基 6-O-苄基-3-苄氨基-2,3-二脱氧-δ± -D-阿拉伯吡喃糖苷),总收率为 50%。