Robust perfluorophenylboronic acid-catalyzed stereoselective synthesis of 2,3-unsaturated <i>O</i>-, <i>C</i>-, <i>N</i>- and <i>S</i>-linked glycosides
作者:Madhu Babu Tatina、Xia Mengxin、Rao Peilin、Zaher M A Judeh
DOI:10.3762/bjoc.15.125
日期:——
A convenient protocol was developed for the synthesis of 2,3-unsaturated C-, O-, N- and S-linked glycosides (enosides) using 20 mol % perflurophenylboronic acid catalyst via Ferrier rearrangement. Using this protocol, D-glucals and L-rhamnals reacted with various C-, O-, N- and S-nucleophiles to give a wide range of glycosides in up to 98% yields with mainly α-anomeric selectivity. The perflurophenylboronic
Gold(III) Chloride and Phenylacetylene: A Catalyst System for the Ferrier Rearrangement, and<i>O</i>-Glycosylation of 1-<i>O</i>-Acetyl Sugars as Glycosyl Donors
作者:Rashmi Roy、Parasuraman Rajasekaran、Asadulla Mallick、Yashwant D. Vankar
DOI:10.1002/ejoc.201402606
日期:2014.9
have developed a new catalystsystem comprising AuCl3 and phenylacetylene that promotes the Ferrierrearrangement of glycals and 2-acetoxymethylglycals with different nucleophiles, and also the O-glycosylation of 1-O-acetylsugars to obtain a variety of useful glycosides at room temperature through relay catalysis. Good anomeric selectivity was observed for the Ferrierrearrangements, whereas the O-glycosylation
Selective activation of “armed’ and ‘'disarmed” glycaldonors enabling the stereo-controlled glycosylations by employing Cu(II)-catalyst as the promoter has been realized. The distinctive stereochemical outcome in the process is mainly influenced by the presence of diverse protecting groups on the donor and the solvent system employed. The protocol is compatible with a variety of aglycones including
[EN] TRANSACETALISATION PROCESS<br/>[FR] METHODE DE TRANSACETALISATION
申请人:UNIV MONASH
公开号:WO2005070911A1
公开(公告)日:2005-08-04
The invention relates to the resolution of racemic mixtures, and in particular to the separation of enantiomers of chiral alcohols utilising recyclable chiral auxiliaries. The present invention also relates to a process for preparing these recyclable chiral auxiliaries using an enantiomerically pure alcohol.
Bi(OTf)3 promoted direct and highly stereoselective glycosylation of “disarmed” and “armed” glycals to synthesize 2-deoxyglycosides has been reported. The tunable and solvent-controlled chemoselective activation of deactivated glycal donors distinguishing the competitive Ferrier and 1,2-addition pathways was discovered to improve substrate scope. The practical versatility of the method has been amply