Bacterial lipopolysaccharides (LPS) are important bio-medical structures, playing a major role in the interaction with human immune systems. Their core regions, containing multiple units of l-glycero-d-manno heptoses (l,d-heptose), are highly conserved structurally (with O3 and O7 glycosidic bonds), making them an epitope of high interest for the potential development of new antibiotics and vaccines. Research in this field has always been restricted by the limited availability of the parent l,d-heptose as well as its biochemical epimeric precursor d-glycero-d-manno heptose (d,d-heptose). This problem of availability has recently been solved by us, through a rapid and efficient practical synthesis of l,d-manno-heptose peracetate demonstrated at scale. Herein we report an optimized, technically simple and versatile synthetic strategy for the differentiation of both the l-glycero and d-glycero-d-manno heptose scaffolds. Our approach is based on an orthoester methodology for the differentiation of all three positions of the sugar core using a O6, O7-tetraisopropyl disiloxyl (TIPDS) protecting group for the exocyclic positions. Furthermore, the regioselective opening toward 7-OH acceptors (6O-FTIPDS ethers) differentiates the exocyclic diol which has been demonstrated with a broader set of substrates and for both manno-heptoses for the first time.

细菌脂多糖（LPS）是重要的生物医学结构，在与人类免疫系统的相互作用中起主要作用。它们的核心区域包含多个升--甘油--d--曼诺 庚糖（升-庚糖），在结构上高度保守（ Ø3和 Ø7个糖苷键），使其成为潜在的表位，可开发新的抗生素和疫苗。该领域的研究一直受到母公司可用性有限的限制。升庚糖及其生化差向异构体前体 d--甘油--d--曼诺 庚糖（d，d-庚糖）。我们最近通过快速有效的实用综合解决了可用性问题升--曼诺-过乙酸庚糖已证实存在规模。在此，我们报告了一种优化的，技术上简单且通用的合成策略，用于区分两种升--甘油 和 d--甘油--d--曼诺庚糖支架。我们的方法基于原酸酯方法，通过使用Ø6， Ø环外位置的7-四异丙基二甲氧基（TIPDS）保护基。此外，区域选择性向7-OH受体开放（6Ø-FTIPDS醚）可以区分环外二醇，这已在更广泛的底物中得到了证明 曼诺-heptose第一次。