title: The vinylfluoro group as an acetonyl cation equivalent: stereoselective synthesis of 6-substituted 4-hydroxy pipecolic acid derivatives.
abstract: An unprecedented cascade of reactions after acid-catalyzed hydrolysis of tert-butyl (2S,5S)-2-tert-butyl-5-(2-fluoroallyl)-3-methyl-4-oxoimidazolidine-1-carboxylate 3a leading to pipecolic acid derivative 5 is presented. The vinylfluoro group is shown to be an acetonyl cation equivalent under acidic conditions. Interestingly, vinylchloro and vinylbromo groups do not show such transformation under the same conditions. The pipecolic acid derivative 5 produced in this way is further used to synthesize (2R,4R,6S)-6-tert-butyl-4-hydroxypiperidine-2-carboxylic acid 9.
authors.affiliation: Organisch-Chemisches Institut, Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany.
authors.forename: Nirupam
authors.initials: N
authors.lastname: Purkayastha
authors.forename: Deepak M
authors.initials: DM
authors.lastname: Shendage
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
authors.forename: Günter
authors.initials: G
authors.lastname: Haufe
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D002412:Cations / Q000737:chemistry*; D048289:Imidazolidines / Q000737:chemistry*; D015394:Molecular Structure; D010875:Pipecolic Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D010880:Piperidines / Q000737:chemistry*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: C547707:(2R,4R,6S)-6-tert-butyl-4-hydroxypiperidine-2-carboxylic acid; C547706:(2S,5S)-2-tert-butyl-5-(2-fluoroallyl)-3-methyl-4-oxoimidazolidine-1-carboxylate; D002264:Carboxylic Acids; D002412:Cations; D048289:Imidazolidines; D010875:Pipecolic Acids; D010880:Piperidines; D014753:Vinyl Compounds; C094924:4-hydroxypipecolic acid