De novo asymmetric synthesis of all-D-, all-L-, and D-/L-oligosaccharides using atom-less protecting groups.
De novo asymmetric synthesis of all-D-, all-L-, and D-/L-oligosaccharides using atom-less protecting groups.
复制标题
DOI：
10.1021/ja305321e
复制
发表时间：
2012-07-25
影响因子：
15
通讯作者：
O'Doherty GA
中科院分区：
文献类型：
--
作者：
Babu RS;Chen Q;Kang SW;Zhou M;O'Doherty GA
寡糖合成因需要多个步骤以及大量选择性保护和脱保护而受到阻碍。在此，我们报告了一种针对各种寡糖基序的高效从头途径，可用于生物和药物结构活性研究。整体效率的关键是明智地使用不对称催化和合成设计。这些绿色原则包括高度立体选择性催化的双向使用（Pd(0)-糖基化/糖基化后）。此外，化学选择性地使用 C-C 和 C-O π-键官能团，作为无原子保护基团以及异头导向基团（通过 Pd-π-烯丙基），突出了获得不同的天然和非天然寡糖（即寡糖的各种 D-/L-非对映异构体以及缺乏 C-2 异头导向基团的脱氧糖）的原子经济方面。例如，仅用 12 个步骤，就从非手性酰基呋喃构建了具有 35 个立体中心的高度支化七糖。
Oligosaccharide synthesis is hindered by the need for multiple steps as well as numerous selective protections and deprotections. Herein we report a highly efficient de novo route to various oligosaccharide motifs, of use for biological and medicinal structure activity studies. The key to the overall efficiency is the judicious use of asymmetric catalysis and synthetic design. These green principles include the bidirectional use of highly stereoselective catalysis (Pd(0)-glycosylation/post-glycosylation). In addition, the chemoselective use of C-C and C-O π-bonds functionality, as atom-less protecting groups as well as an anomeric directing group (via a Pd-π-allyl), highlights the atom economical aspects of the route to a divergent set of natural and unnatural oligosaccharides (i.e., various D-/L-diastereomers of oligosaccharide as well as deoxysugars which lack C-2 anomeric directing groups). For example, in only 12 steps, the construction of a highly branched hepta-saccharide with 35 stereocenters was accomplished from an achiral acylfuran.