The synthesis of vitamin E sugar 1,2-orthoesters

摘要

In this study, 3,4,6-tri-O-acetyl-1,2-O-(1-tocopheroxyethylidene)--d-glucopyranose (sugar 1,2-orthoester) was synthesized with good and moderate yields in the presence of an N,N-diisopropylethylamine/tetrabutylammonium iodide system via a reaction of -tocopherol with sugar halides. The utility of sugar - and -chlorides, -bromides, and -iodide in the synthesis of aryl (-tocopherol, 2,2,5,7,8-pentamethylchroman-6-ol and 2,6-dimethylphenol) 1,2-orthoesters was investigated. The stereoselective formation of exo-1,2-orthoesters was confirmed using H-1 and C-13 NMR spectroscopy.