Stereocontrolled Synthesis of 2-Deoxy-galactopyranosides via Isopropylidene-Protected 6-<i>O</i>-Silylated Donors
作者:Dan-Mei Yang、Yue Chen、Ryan P. Sweeney、Todd L. Lowary、Xing-Yong Liang
DOI:10.1021/acs.orglett.8b00632
日期:2018.4.20
The stereocontrolled synthesis of 2-deoxy-d-arabino-hexopyranosides (“galactopyranosides”) using 3,4-O-isopropylidene-6-O-tert-butyldiphenylsilyl-protected glycosyl donors is reported. 2-Deoxy-thioglycoside 3e gives excellent α-selectivity, while galactal 9 leads to, in a two-step protocol, 2-deoxy-β-glycosides in high stereoselectivity. The selectivity of both reagents is believed to arise from the
2-脱氧的立体控制合成d -阿拉伯-hexopyranosides使用3,4-(“吡喃半乳糖苷”)ö异亚丙基-6- ø -叔报道-butyldiphenylsilyl保护的糖基供体。2-脱氧-硫代糖苷3e具有出色的α-选择性,而半乳糖9在两步操作中可产生高立体选择性的2-脱氧-β-糖苷。据信两种试剂的选择性是由跨越O-3和O-4的异亚丙基缩醛与O-6上的空间上需要的甲硅烷基基团的组合产生的。该方法的实用性通过合成含有2-deoxyα-和β- d的三糖来证明-半乳糖吡喃糖基残基。