175652-39-8Relevant academic research and scientific papers
A convenient route to higher sugars by two-carbon chain elongation using Wittig/dihydroxylation reactions
Jorgensen,Iversen,Madsen
, p. 4625 - 4629 (2007/10/03)
The combination of a Wittig olefination and a dihydroxylation reaction constitutes a facile synthetic protocol for the transformation of unprotected carbohydrates into higher sugars. The Wittig reaction is carried out with tert-butyl or diphenylmethyl ester stabilized phosphoranes to give (E)-configured α,β-unsaturated esters as the only products in most cases. These are dihydroxylated in a diastereoselective fashion using OsO4/NMO. The stereochemical outcome in the dihydroxylation follows Kishi's empirical 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 higher sugars with the galacto configuration at the reducing end. The two steps can either be carried out individually or, more efficiently, as a one-pot procedure.
Wittig chain extension of unprotected carbohydrates: Formation of carbohydrate-derived α,β-unsaturated esters
Railton, Craig J.,Clive, Derrick L.J.
, p. 69 - 77 (2007/10/03)
Unprotected carbohydrates react with Wittig reagents 6 and 7 to give unsaturated esters. This homologation has been used to prepare an intermediate (18) previously employed in a synthesis of Kdo (19).
