Regioselective Synthesis of Difluorinated <i>C</i>-Furanosides Involving a Debenzylative Cycloetherification
作者:Julien A. Delbrouck、Valentin N. Bochatay、Abdellatif Tikad、Stéphane P. Vincent
DOI:10.1021/acs.orglett.9b01878
日期:2019.7.19
A highly regioselective synthesis of valuable gem-difluorinated C-furanosides from unprotected aldoses via a debenzylative cycloetherification (DBCE) reaction induced by diethylaminosulfur trifluoride is descibed. The scope and limitations of this DBCE reaction are described using a series of commercially available pentoses and hexoses to afford, without selective protection/deprotection sequences
Synthesis of sialic acid derivatives based on chiral substrate-controlled stereoselective aldol reactions using pyruvic acid oxabicyclo[2.2.2]octyl orthoester
accomplished based on substrate-controlled asymmetric aldol reactions between sterically complicated aldehydes easily prepared from commercially available carbohydrates and a novel pyruvic acid oxabicyclo[2.2.2]octyl orthoester. Systematic aldol reactionstudies using chiral aldehydes revealed that α,β,γ-benzyloxy-substituted aldehydes with an α,β-anti relative configuration preferentially provided the
唾液酸及其类似物的合成是基于易于从市售碳水化合物制备的空间复杂醛与新型丙酮酸草酸双环[2.2.2]辛基原酸酯之间的受底物控制的不对称醛醇缩合反应完成的。使用手性醛的系统羟醛反应研究表明,具有α,β-反相对构型的α,β,γ-苄氧基取代的醛优先为Felkin产物提供具有高非对映选择性的4,5-抗构型。具有α,β-顺式排列的α,β,γ-苄氧基取代的醛中的相对β,γ构型对醛醇缩合反应中形成的立构中心的非对映选择性具有次要作用。syn - β ,γ-抗苄氧基醛显示出比α,β- syn - β ,γ- syn苄氧基醛更高的非对映选择性,从而生成Felkin产物。
Synthesis of trifluoromethyl analogue of L-fucose and 6-deoxy-D-altrose
作者:Romesh C. Bansal、Barbara Dean、Sen-itiroh Hakomori、Tatsushi Toyokuni
DOI:10.1039/c39910000796
日期:——
Trifluoromethylation of the acyclicderivative of D-lyxose, 3, with trifluoromethyltrimethylsilane in the presence of tetrabutylammonium fluoride yielded a mixture of trifluoromethyl adducts, 5a and b, which was converted to 6,6,6-trifluoro-L-fucose 9a and 6-deoxy-6,6,6-trifluoro-D-altrose 9bvia selective oxidation of the primary hydroxy group involving treatment of the trimethylsiloxy derivatives, 7a and b, with
Synthesis of acyclic galactitol- and lyxitol-aminophosphonates as inhibitors of UDP-galactopyranose mutase
作者:Weidong Pan、Christophe Ansiaux、Stéphane P. Vincent
DOI:10.1016/j.tetlet.2007.04.113
日期:2007.6
UDP-galactopyranose mutase (UGM) catalyzes the isomerization of UDP-galactopyranose (UDP-Galp) into UDP-galactofuranose (UDP-Ga1f), an essential step of the mycobacterial cell wall biosynthesis. Acyclic alditol-aminophosphonates in the D-galactose and D-lyxose series were designed as mimics of high energy intermediates of the UGM catalyzed isomerization. Interestingly, the D-lyxitol-aminophosphonate displayed better inhibition properties than the D-galactitol-aminophosphonatc. (c) 2007 Elsevier Ltd. All rights reserved.