title: One-pot conversion of glycals to cis-1,2-isopropylidene-alpha-glycosides.
abstract: Described is a general method for the conversion of glycals to the corresponding 1,2-cis-isopropylidene-alpha-glycosides. Epoxidation of glycals with dimethyldioxirane followed by ZnCl(2)-catalyzed addition of acetone converted a variety of protected glycals into 1,2-cis-isopropylidene-alpha-glycosides in good yield. The reaction is compatible with a range of protecting groups, including esters, benzyl ethers, and silyl ethers, as well as free hydroxyl groups. This method has been applied to develop a synthesis of protected glucuronic acid 1, a key intermediate in the synthesis of glycosaminoglycans. Compound 1 was produced in seven steps and 32% overall yield.
authors.affiliation: Massachusetts Institute of Technology, 77 Massachusetts Avenue 18-292, Cambridge, Massachusetts 02139, USA.
authors.forename: Gregory J S
authors.initials: GJ
authors.lastname: Lohman
authors.forename: Peter H
authors.initials: PH
authors.lastname: Seeberger
mesh_terms: D002125:Calcium Gluconate / Q000138:chemical synthesis; D020723:Glucuronic Acid / Q000138:chemical synthesis; D006025:Glycosaminoglycans / Q000138:chemical synthesis; D006027:Glycosides / Q000138:chemical synthesis*
chemical_list: D006025:Glycosaminoglycans; D006027:Glycosides; D020723:Glucuronic Acid; D002125:Calcium Gluconate