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
Stereoselective synthesis of sugar allenes and their hydrosilylation catalyzed by biscobaltoctacarbonyl
作者:Guobin Huang、Minoru Isobe
DOI:10.1016/s0040-4020(01)01066-3
日期:2001.12
Stereoselective introduction of allenyl group to glycals has been developed with propargyltrimethylsilane under the catalysis of a Lewis acid to produce largely the a-sugar allenes in good yields. The subsequent hydrosilylations of these sugar allenes were catalyzed by biscobaltoctacarbonyl to obtain the corresponding vinylsilanes. Stereochemical selectivity is also discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.