1028796-13-5Relevant academic research and scientific papers
Gold(I)-Catalyzed glycosylation with glycosyl ortho-alkynylbenzoates as donors: General scope and application in the synthesis of a cyclic triterpene saponin
Li, Yao,Yang, Xiaoyu,Liu, Yunpeng,Zhu, Cunsheng,Yang, You,Yu, Biao
supporting information; experimental part, p. 1871 - 1882 (2010/06/20)
Glycosyl ortho-alkynylbenzoates have emerged as a new generation of donors for glycosidation under the catalysis of gold(I) complexes such as Ph 3PAuOTf and Ph3PAuNTf2 (Tf= trifluoromethanesulfonate). A wide variety of these donors, including 2-deoxy sugar and sialyl donors, are easily prepared and shelf stable. The glycosidic coupling yields with alcohols are gener-ally excellent; even direct coupling with the poorly nucleophilic amides gives satisfactory yields. Moreover, excellent α-selective glycosylation with a 2-deoxy sugar donor and β-selective sialylation have been realized. Application of the present glycosylation protocol in the efficient synthesis of a cyclic triterpene tetrasaccharide have further demonstrated the versatility and efficacy of this new method, in that a novel chemoselective glycosylation of the carboxylic acid and a new one-pot sequential glycosylation sequence have been implemented.
Efficient synthesis of a sialic acid α(2→3)galactose building block and its application to the synthesis of ganglioside GM3
Liu, Yunpeng,Ruan, Xiaohong,Li, Xiangpeng,Li, Yingxia
, p. 4287 - 4290 (2008/09/20)
(Chemical Equation Presented) Glycosylation of various galactose derivatives with O-acetylated sialic acid N-phenyltrifluoroacetimidate as the donor was investigated. Efficient α(2,3)sialylation of galactose, with up to 73% yield and 8.4:1 stereoselectivity, was realized when 2,3,4-unprotected galactose derivatives and TBSOTf were used as acceptors and promoter, respectively. Sialylation of 2-(trimethylsilyl)ethyl 6-O-tert- butyldiphenylsilyl-β-D-galactopyranoside (3f) gave the best result, and the resultant Neu5Ac α(2→3)Gal disaccharide was successfully used in the synthesis of ganglioside GM3.
