Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India.
Institute of Chemistry , Academia Sinica , Taipei 115 , Taiwan.
Chem Rev. 2018 Sep 12;118(17):8025-8104. doi: 10.1021/acs.chemrev.8b00036. Epub 2018 Jun 5.
Carbohydrates, which are ubiquitously distributed throughout the three domains of life, play significant roles in a variety of vital biological processes. Access to unique and homogeneous carbohydrate materials is important to understand their physical properties, biological functions, and disease-related features. It is difficult to isolate carbohydrates in acceptable purity and amounts from natural sources. Therefore, complex saccharides with well-defined structures are often most conviently accessed through chemical syntheses. Two major hurdles, regioselective protection and stereoselective glycosylation, are faced by carbohydrate chemists in synthesizing these highly complicated molecules. Over the past few years, there has been a radical change in tackling these problems and speeding up the synthesis of oligosaccharides. This is largely due to the development of one-pot protection, one-pot glycosylation, and one-pot protection-glycosylation protocols and streamlined approaches to orthogonally protected building blocks, including those from rare sugars, that can be used in glycan coupling. In addition, new automated strategies for oligosaccharide syntheses have been reported not only for program-controlled assembly on solid support but also by the stepwise glycosylation in solution phase. As a result, various sugar molecules with highly complex, large structures could be successfully synthesized. To summarize these recent advances, this review describes the methodologies for one-pot protection and their one-pot glycosylation into the complex glycans and the chronological developments associated with automated syntheses of oligosaccharides.
碳水化合物广泛分布于生命的三个领域，在各种重要的生物过程中发挥着重要作用。获得独特且均一的碳水化合物材料对于了解它们的物理性质、生物功能和与疾病相关的特征非常重要。从天然来源中以可接受的纯度和数量分离碳水化合物是困难的。因此，具有明确结构的复杂糖通常最方便通过化学合成获得。在合成这些高度复杂的分子时，碳水化合物化学家面临两个主要障碍：区域选择性保护和立体选择性糖基化。在过去的几年中，通过一锅法保护、一锅法糖基化和一锅法保护-糖基化方案以及对正交保护砌块（包括稀有糖的砌块）的简化方法，这些问题得到了彻底解决，并加快了寡糖的合成速度。这主要是由于发展了一锅法保护和一锅法糖基化，以及可用于糖苷偶联的正交保护砌块（包括稀有糖的砌块）的流线型方法。此外，还报道了用于寡糖合成的新自动化策略，不仅用于在固相上的程控组装，还用于在溶液相中逐步糖基化。因此，可以成功合成具有高度复杂、大分子结构的各种糖分子。为了总结这些最新进展，本文综述了一锅法保护及其一锅法糖基化合成复杂聚糖的方法，以及与寡糖自动化合成相关的时间顺序发展。
