A Convenient Route to Higher Sugars by Two-Carbon Chain Elongation Using Wittig/Dihydroxylation Reactions
作者:Morten Jørgensen、Erik H. Iversen、Robert Madsen
DOI:10.1021/jo010128e
日期:2001.6.1
rule and gives high diastereoselectivity (5:1-8:1) when starting from sugars with the 2,3-threo configuration. When starting from sugars with the 2,3-erythro configuration, the diastereoselectivity in the dihydroxylation is low (2:1-2.5:1). As a result, the Wittig/dihydroxylation protocol is most effective for producing highersugars with the galacto configuration at the reducing end. The two steps can
Efficient Synthesis of Enantiopure Conduritols by Ring-Closing Metathesis
作者:Morten Jørgensen、Erik H. Iversen、Andreas L. Paulsen、Robert Madsen
DOI:10.1021/jo0101297
日期:2001.6.1
to enantiopure conduritols are described starting from the chiral pool. In both cases, the cyclohexene ring is assembled via ring-closing olefin metathesis. The terminal diene precursers for the metathesis reaction are prepared either from octitols or from tartaric acids. The former route involves a new method for selective bromination of the primary positions in long-chain carbohydrate polyols. Subsequent