Convenient Synthesis of 4,6-<i>O</i>-Pyruvate Acetal Containing Glycosides via Tetraisopropyldisiloxanediyl Protected Sugars
作者:Thomas Ziegler、Elisabeth Eckhardt、Karin Neumann、Veronique Birault
DOI:10.1055/s-1992-26291
日期:——
Treatment of alkyl D-glycopyranosides and alkyl or phenyl 1-thio-ß-D-glycopyranosides 1 with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane gave the corresponding 4,6-O-(1,1,3,3-tetraisopro-pyldisiloxane-1,3-diyl) protected glycosides 2 which were subsequently benzoylated with benzoyl bromide to give the fully blocked glycosides 3. Reaction of the latter with methyl pyruvate and a catalytic amount of trimethylsilyl trifluoromethanesulfonate gave alkyl and phenyl 4,6-O-[1-(methoxycarbonyl)ethylidene]glycopyranosides 4 with high diastereoselectivity.
烷基 D-吡喃葡糖苷和烷基或苯基1-硫-ß-D-吡喃葡糖苷 1 与1,3-二氯-1,1,3,3-四异丙基二硅氧烷反应,得到相应的4,6-O-(1,1,3,3-四异丙基二硅氧烷-1,3-二基)保护的糖苷 2,随后用苯甲酰溴进行苯甲酰化,得到完全保护的糖苷 3。后者与丙酮酸甲酯和少量三甲基硅基三氟甲磺酸酯反应,以高非对映选择性得到烷基和苯基4,6-O-[1-(甲氧羰基)乙叉]吡喃葡糖苷 4。