School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
Carbohydr Res. 2012 Feb 1;348:6-13. doi: 10.1016/j.carres.2011.07.020. Epub 2011 Jul 26.
Novel oxathiane spiroketal donors have been synthesised and activated via an umpolung S-arylation strategy using 1,3,5-trimethoxybenzene and 1,3-dimethoxybenzene. The comparative reactivity of the resulting 2,4,6-trimethoxyphenyl (TMP)- and 2,4-dimethoxyphenyl (DMP)-oxathiane spiroketal sulfonium ions is discussed, and their α-stereoselectivity in glycosylation reactions is compared to the analogous TMP- and DMP-sulfonium ions derived from an oxathiane glycosyl donor bearing a methyl ketal group. The results show that the stereoselectivity of the oxathiane glycosyl donors is dependent on the structure of the ketal group and reactivity can be tuned by varying the substituent on the sulfonium ion.
新型噁唑烷硫酮类供体已通过使用 1,3,5-三甲氧基苯和 1,3-二甲氧基苯的反转 S-芳基化策略进行合成和激活。讨论了所得的 2,4,6-三甲氧基苯基（TMP）和 2,4-二甲氧基苯基（DMP）噁唑烷硫酮螺环硫翁离子的相对反应性，并将其在糖苷化反应中的α-立体选择性与源自带有甲缩醛基团的噁唑烷糖基供体的类似 TMP-和 DMP-硫翁离子进行了比较。结果表明，噁唑烷糖基供体的立体选择性取决于缩醛基团的结构，并且可以通过改变硫翁离子上的取代基来调节反应性。
