Guo Tianyun, Zhang Yufeng, Li Yanyang, Liu Jian, Wang Xiaolei
Department of Chemistry and School of Pharmacy, China State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China.
Org Lett. 2025 Jan 24;27(3):789-794. doi: 10.1021/acs.orglett.4c04425. Epub 2025 Jan 12.
Here we present a regio- and stereoselective alkylation approach for unprotected saccharides using synergistic boronic acid and photoredox catalysis. Targeting the equatorial C-H bond of the -1,2-diol motif, this method employs MeB(OH) as a catalyst. Mechanistic investigations indicate that the formation of a tetracoordinate boron species, resulting from the interaction between the cyclic boronic diol ester and a free hydroxyl group in the saccharide, is critical to this transformation. Notably, this method enables efficient late-stage modification of complex carbohydrates, such as raffinose and the drug digoxin, expanding opportunities for carbohydrate functionalization.
在此，我们展示了一种使用协同硼酸和光氧化还原催化对未保护糖类进行区域和立体选择性烷基化的方法。该方法以 -1,2-二醇基序的赤道面 C-H 键为目标，采用 MeB(OH) 作为催化剂。机理研究表明，环状硼酸二醇酯与糖类中游离羟基之间的相互作用导致形成四配位硼物种，这对该转化至关重要。值得注意的是，该方法能够对复杂碳水化合物（如棉子糖和药物地高辛）进行高效的后期修饰，为碳水化合物功能化拓展了机会。
