title: Stereoselective functionalisation of cis- and trans-2-ferrocenyl-3-pivaloyl-4-alkyl-1,3-oxazolidin-5-ones: asymmetric synthesis of (R)- and (S)-2-alkyl-2-aminopent-4-enoic acids and (2R,3S)-2-amino-2-methyl-3-hydroxy-3-phenylpropanoic acid.
abstract: Treatment of a range of cis- and trans-2-ferrocenyl-3-pivaloyl-4-alkyl-1,3-oxazolidin-5-ones with LDA followed by the addition of allyl bromide promotes highly stereoselective allylation (>98% de) at the 4-position of the oxazolidinone ring anti to the stereodirecting 2-ferrocenyl group. Hydrolysis of the resultant 4,4-disubstituted oxazolidinones (>98% de) yields enantiomeric (R)- and (S)-2-alkyl-2-aminopent-4-enoic acids in high ee. Furthermore, the aldol reaction of the lithium enolate of cis-2-ferrocenyl-3-pivaloyl-4-methyl-1,3-oxazolidin-5-one with benzaldehyde followed by in situ O-protection affords O-protected aldol products in >98% de, with hydrolysis affording (2R,3S)-2-amino-2-methyl-3-hydroxy-3-phenylpropanoic acid in >98% de.
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, UKOX1 3TA.
authors.forename: Francisco
authors.initials: F
authors.lastname: Alonso
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Davies
authors.forename: Almut S
authors.initials: AS
authors.lastname: Elend
authors.forename: Michael A
authors.initials: MA
authors.lastname: Leech
authors.forename: Paul M
authors.initials: PM
authors.lastname: Roberts
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Smith
authors.forename: James E
authors.initials: JE
authors.lastname: Thomson
mesh_terms: D000501:Allylglycine / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D023303:Oxazolidinones / Q000737:chemistry*; D010666:Phenylpropionates / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: C538956:(2R,3S)-2-amino-2-methyl-3-hydroxy-3-phenylpropanoic acid; D023303:Oxazolidinones; D010666:Phenylpropionates; D000501:Allylglycine