已经制备并表征了多种新的同手性碳水化合物衍生的硫醇,其中SH基团连接到异头碳原子上。这些硫醇已被评估为质子极性反转催化剂,可介导三苯基硅烷向前手性亚甲基内酯中的H 2 C CR 1 R 2基团进行对映选择性自由基链加成,从而得到一般型Ph 3 SiCH 2 CHR 1 R 2的手性加合物。; 化学收率一直很高。进行了硫醇结构的系统改变,目的是增加前手性烷基Ph从SH基团夺取氢原子的对映选择性。3 SICH 2 CR 1 - [R 2。尽管在60℃下进行的反应中可以以高对映体过量获得加合物,但是与使用简单的四-O-乙酰基-β-吡喃葡萄糖和-β-甘露吡喃硫醇作为催化剂所获得的相比,对映选择性没有显着提高。据发现,吡喃糖硫醇的α端基异构体是无效的,在对映选择性介导氢的原子转移到自由基博士3 SICH 2 CR 1 - [R 2。所有的β-吡喃糖硫醇以相同的方式给出不对称诱导,但是两个具有较少极性
Synthesis of octyl O- and S-glycosides related to the GPI anchor of Trypanosoma brucei and their in vitro galactosylation by trypanosomal α-galactosyltransferases
作者:T Ziegler
DOI:10.1016/s0008-6215(96)00215-7
日期:1996.12.13
Octyl O- and S-glycosides of mono- to tri-saccharides related to the core structure alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->6)-alpha-D-Manp of the GPI anchor of Trypanosoma brucei have been prepared via regioselective protodesilylation and glycodesilylation of octyl O- and S-glycosides of 2-O-benzoyl-4,6-O-(1,1,3,3-tetraisopropyl-1,3-disiloxane-1,3-diyl)-alpha-D-mannopyranoside. The synthetic saccharides have been used as substrates for enzymatic alpha-galactosylation with membrane fractions of bloodstream forms of T. brucei strain 427 variants MIT at 1.4, MIT at 1.2, and MIT at 1.5, respectively. (C) 1996 Elsevier Science Ltd.
Nikolaev, Andrey V.; Rutherford, Trevor J.; Ferguson, Michael A. J., Journal of the Chemical Society. Perkin transactions I, 1995, # 16, p. 1977 - 1988
作者:Nikolaev, Andrey V.、Rutherford, Trevor J.、Ferguson, Michael A. J.、Brimacombe, John S.