title: Racemization in the use of N-(9-(9-phenylfluorenyl))serine-derived cyclic sulfamidates in the synthesis of delta-keto alpha-amino carboxylates and prolines.
abstract: [reaction: see text]Ring opening of enantiopure N-(9-(9-phenylfluorenyl)serine-derived cyclic sulfamidates with beta-keto esters, beta-keto ketones, and dimethyl malonate gave a variety of gamma-substituted amino acid analogues in racemic form. Investigation of the mechanism for racemization revealed that beta-elimination occurred to form a dehydroalanine intermediate that underwent subsequent Michael addition.
authors.affiliation: Département de chimie, Université de Montréal, Québec, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Wei
authors.forename: W D
authors.initials: WD
authors.lastname: Lubell
mesh_terms: D002264:Carboxylic Acids / Q000138:chemical synthesis*; D003499:Cyclic S-Oxides / Q000737:chemistry*; D010080:Oxazoles / Q000737:chemistry*; D011392:Proline / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013449:Sulfonamides / Q000737:chemistry*
chemical_list: D002264:Carboxylic Acids; D003499:Cyclic S-Oxides; D010080:Oxazoles; D013449:Sulfonamides; D011392:Proline