title: Synthesis of allo- and epi-inositol via the NHC-catalyzed carbocyclization of carbohydrate-derived dialdehydes.
abstract: A synthesis of carbocyclic sugars from carbohydrate-derived dialdehydes using organocatalysis has been developed. Sorbitol, mannitol, and galactitol were converted via 1,6-tritylation, perbenzylation or permethylation, detritylation, and Swern oxidation into 2,3,4,5-tetra-O-alkyl-dialdoses that were cyclized via the benzoin reaction promoted by a triazolium carbene. Manno- and galacto-configured dialdehydes gave predominantly single inosose stereoisomers in up to 75% yield if the mixture was acetylated prior to isolation while the gluco-dialdehyde afforded a mixture of three stereoisomers in 61% overall yield. The inososes were stereospecifically reduced using sodium borohydride and then deprotected to give allo- and epi-inositol in good yield that confirmed the structural and stereochemical assignments.
authors.affiliation: School of Science and Technology, University of New England , Armidale, New South Wales 2351, Australia.
authors.forename: Kieran P
authors.initials: KP
authors.lastname: Stockton
authors.forename: Ben W
authors.initials: BW
authors.lastname: Greatrex
authors.forename: Dennis K
authors.initials: DK
authors.lastname: Taylor