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
A Siloxane-Bridged Glycosyl Donor Enables Highly Stereoselective β-Xylulofuranosylation
作者:Bo-Shun Huang、Todd L. Lowary
DOI:10.1021/acs.joc.0c01008
日期:2020.12.18
We report a siloxane-protected donor (7) for the highlystereoselective formation of β-(2,3-cis)-xylulofuranosyl bonds. Glycosylation reactions with 7 gave >80% yields, and only β-xylulofuranosides were isolated in all cases. The utility of 7 for the synthesis of complex glycans was shown by its successful application to the preparation of the repeating unit from the lipopolysaccharide O-antigen of
Tin(IV) chloride mediated glycosylation in arabinofuranose, galactofuranose and rhamnopyranose
作者:Ashish K. Pathak、Yahya A. El-Kattan、Namita Bansal、Joseph A. Maddry、Robert C. Reynolds
DOI:10.1016/s0040-4039(98)00051-3
日期:1998.3
Using tin(IV) chloride, O-glycosylation reactions were performed on peracylated D-arabinofuranose, d-galactofuranose and l-rhamnofuranose as well as 1-bromo-d-arabinofuranoses at room temperature in good anomeric purities and yields. In these circumstances, this coupling method has certain advantages over standard glycosylation reactions, such as the Koenigs-Knorr methods which use the 1-halosugar