Racemization in the use of N-(9-(9-phenylfluorenyl))serine-derived cyclic sulfamidates in the synthesis of delta-keto alpha-amino carboxylates and prolines.
[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.
Wei
L
L
Département de chimie, Université de Montréal, Québec, Canada.
Lubell
W D
WD
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*
D002264:Carboxylic Acids; D003499:Cyclic S-Oxides; D010080:Oxazoles; D013449:Sulfonamides; D011392:Proline