3, readily prepared in two steps from propargyl bromide, 1, is converted to methyl 2-deoxy-D-xylofuranoside, 13, and to the unnatural L-enantiomer, 12, in 5 steps and 50% overall yield, utilizing asymmetric dihydroxylation (AD) of alkene 7 for introduction of chirality. A similar strategy from the isomeric Z-allylic alcohol, 4, afforded the 2-deoxy-L-ribofuranoside, but in modest enantiomeric excess
从炔丙基
溴1中分两步轻松制得的炔醇3分5步转化为甲基2-脱氧-D-木
呋喃糖苷13和非天然L-对映体12,总产率为50%,利用烯烃7的不对称二羟基化(AD)引入手性。来自异构的Z-
烯丙醇4的类似策略提供了2-脱氧-
L-呋喃核糖苷,但是对映体过量。