Bradshaw G A, Colgan A C, Allen N P, Pongener I, Boland M B, Ortin Y, McGarrigle E M
Centre for Synthesis & Chemical Biology , UCD School of Chemistry , University College Dublin , Belfield , Dublin 4 , Ireland . Email:
Chem Sci. 2018 Oct 22;10(2):508-514. doi: 10.1039/c8sc02788a. eCollection 2019 Jan 14.
Thiouracil catalyzes stereoselective glycosylations with galactals in loadings as low as 0.1 mol%. It is proposed that in these glycosylations thiouracil, monothiophthalimide, and the previously reported catalyst, Schreiner's thiourea, do not operate a double H-bonding mechanism but rather by Brønsted acid/base catalysis. In addition to the synthesis of 2-deoxyglycosides and glycoconjugates, we report the first organocatalytic synthesis of 1,1'-linked trehalose-type sugars.
硫脲能以低至0.1 mol%的用量催化半乳糖与半缩醛的立体选择性糖基化反应。据推测，在这些糖基化反应中，硫脲、单硫代邻苯二甲酰亚胺以及先前报道的催化剂施赖纳硫脲并非通过双氢键机制起作用，而是通过布朗斯特酸碱催化。除了合成2-脱氧糖苷和糖缀合物外，我们还报道了首例1,1'-连接的海藻糖型糖的有机催化合成。
