Carbohydrate-derived iminium salt organocatalysts for the asymmetric epoxidation of alkenes
作者:Philip C. Bulman Page、Yohan Chan、John Liddle、Mark R.J. Elsegood
DOI:10.1016/j.tet.2014.07.052
日期:2014.10
A new family of carbohydrate-based dihydroisoquinolinium salts has been prepared and tested for potential as asymmetric catalysts for the epoxidation of unfunctionalized alkene substrates, providing up to 57% ee in the product epoxides.
Electrophilic azidation of tri-O-benzyl-2-deoxy-D-galactono-1,5-lactone 3 with triisopropylphenylsulfonyl azide, followed by selective reduction with diisobutylaluminium hydride, yielded tri-O-benzyl-2-azido-2-deoxy-D-galactopyranose 5 as the sole product in 80% yield, while the same sequence of reactions with the 2-deoxy-glucono-1,5-lactone derivative 8 afforded only tri-O-benzyl-2-azido-2-deoxy-D-mannopyranose 10 in 65% yield.
Improved Synthesis of Phytosphingosine and Dihydrosphingosine from 3,4,6-Tri-O-benzyl-D-galactal
作者:Youhong Niu、Xiaoping Cao、Xin-Shan Ye
DOI:10.1002/hlca.200890076
日期:2008.4
An efficient and facile synthesis of phytosphingosine and dihydrosphingosine derivatives is described with less steps and in improved overall yield (66–72%) starting from commercially available tri-O-benzyl-D-galactal. The key steps include Wittig reaction, Mitsunobu transformation, reduction, and deprotection.
AuCl<sub>3</sub>-Catalyzed Hemiacetal Activation for the Stereoselective Synthesis of 2-Deoxy Trehalose Derivatives
作者:Robin Jeanneret、Carlo Walz、Maarten van Meerbeek、Sarah Coppock、M. Carmen Galan
DOI:10.1021/acs.orglett.2c02530
日期:2022.9.2
A new practical, catalytic, and highly stereoselective method for directly accessing 1,1-α,α′-linked 2-deoxy trehalose analogues via AuCl3-catalyzed dehydrative glycosylation using hemiacetal glycosyl donors and acceptors is described. The method relies on the chemoselective Brønsted acid-type activation of tribenzylated 2-deoxy hemiacetals in the presence of other less reactive hemiacetals.
TFA-induced conversion of glycals to 2-deoxy-sugars and their utility in synthesizing 2-deoxy-glycosyl esters
作者:Bindu Tiwari、Ram Pratap Pandey、Nazar Hussain
DOI:10.1039/d4nj00945b
日期:——
of 2-deoxy-glycosyl esters with carboxylic acids. This library of glycosyl esters was synthesized by employing a range of acids, including readily available drugs like indomethacin, tolmetin, and others. A plausible route for generating 2-deoxy sugars was also demonstrated where the double bond of glycals is activated with an activator and simultaneous attack of a hydroxyl group on the anomeric carbon