Université Paris-Sud and CNRS, Laboratoire de Synthèse de Biomolécules, Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR 8182, 91405 Orsay (France); Department of Chemical Engineering, HCMC University of Technology, VNU-HCM, 268 Ly Thuong Kiet, District 10, Ho Chi Minh City (Vietnam).
Angew Chem Int Ed Engl. 2014 Jun 10;53(24):6184-7. doi: 10.1002/anie.201402891. Epub 2014 Apr 24.
The umpolung of glycals with samarium diiodide offers a simple route to novel carbohydrate-derived nucleophilic reagents in a single step using a readily available reductant. The corresponding allyl samarium reagent that arises from the hexose series reacts with ketones at the C3 position with high stereoselectivity; carbon-carbon bond formation takes place only anti to the substituent at the C4 position of the dihydropyran ring. For the sialic acid series, the completely regio- and stereoselective coupling process of the samarium reagent occurs at the anomeric carbon atom and provides a new approach to the α-C-glycosides of N-acetyl neuraminic acid.
用钐二碘化物使糖脂反转，使用易得的还原剂，在一步反应中就可以得到新型的衍生自碳水化合物的亲核试剂。从己糖系列生成的相应的烯丙基钐试剂与酮在 C3 位具有高立体选择性地反应；碳-碳键的形成仅发生在二氢吡喃环的 C4 位取代基的反式。对于唾液酸系列，烯丙基钐试剂的完全区域和立体选择性偶联反应发生在糖苷碳原子上，为 N-乙酰神经氨酸的 α-C-糖苷提供了一种新方法。
