title: Studies on the generation of enolate anions from butane-2,3-diacetal protected glycolic acid derivatives and subsequent highly diastereoselective coupling reactions with aldehydes and acid chlorides.
abstract: Highly diastereoselective coupling reactions of enolates derived from butane-2,3-diacetal protected glycolic acids 1 and 2 and their alkylated derivatives with aldehydes are reported together with their efficient acid-catalysed deprotection to yield enantiopure anti-2,3-dihydroxyesters. A procedure to provide the corresponding syn-2,3-dihydroxyesters is also described in two cases, proceeding via an acylation-reduction sequence. An usual double addition reaction of butane-2,3-diacetal protected glycolic acid to small aliphatic acid chlorides provides a synthetically useful, densely-functionalised lactone after acidic deprotection.
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK CB2 1EW. svl1000@cam.ac.uk
authors.forename: Steven V
authors.initials: SV
authors.lastname: Ley
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Dixon
authors.forename: Richard T
authors.initials: RT
authors.lastname: Guy
authors.forename: Maria A
authors.initials: MA
authors.lastname: Palomero
authors.forename: Alessandra
authors.initials: A
authors.lastname: Polara
authors.forename: Felix
authors.initials: F
authors.lastname: Rodriguez
authors.forename: Tom D
authors.initials: TD
authors.lastname: Sheppard
mesh_terms: D000080:Acetals / Q000737:chemistry*; D000143:Acids / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry*; D000838:Anions / Q000138:chemical synthesis*; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D007659:Ketones / Q000138:chemical synthesis*; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D000080:Acetals; D000143:Acids; D000447:Aldehydes; D000838:Anions; D006843:Hydrocarbons, Chlorinated; D007659:Ketones; C442342:butane-2,3-diacetal glycolic acid