title: Stereoselective access to fluorinated and non-fluorinated quaternary piperidines: synthesis of pipecolic acid and iminosugar derivatives.
abstract: The preparation of optically pure quaternary piperidines, both fluorinated and non-fluorinated, has been achieved from a chiral imino lactone derived from (R)-phenylglycinol. In the case of the fluorinated derivatives, the addition of (trifluoromethyl)trimethylsilane (TMSCF(3)) followed by iodoamination and migration of the CF(3) group allowed access to four derivatives of α-(trifluoromethyl)pipecolic acid. A theoretical study of the CF(3)-group rearrangement has been carried out to help establish the reaction mechanism of this uncommon transformation. Moreover, a route to trifluoromethyl-substituted iminosugars was also developed through the diastereoselective dihydroxylation of suitable synthetic intermediates. Conversely, alkylation of the starting substrate and subsequent cross-metathesis and aza-Michael reactions led to α-alkyl derivatives of the target compounds.
authors.affiliation: Departmento de Química Orgánica, Universidad de Valencia, 46100 Burjassot, Valencia, Spain. santos.fustero@uv.es
authors.forename: Santos
authors.initials: S
authors.lastname: Fustero
authors.forename: Laia
authors.initials: L
authors.lastname: Albert
authors.forename: Natalia
authors.initials: N
authors.lastname: Mateu
authors.forename: Gema
authors.initials: G
authors.lastname: Chiva
authors.forename: Javier
authors.initials: J
authors.lastname: Miró
authors.forename: Javier
authors.initials: J
authors.lastname: González
authors.forename: José Luis
authors.initials: JL
authors.lastname: Aceña
mesh_terms: D054879:Halogenation; D050111:Imino Sugars / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D010875:Pipecolic Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D010880:Piperidines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D050111:Imino Sugars; D010875:Pipecolic Acids; D010880:Piperidines; C031345:pipecolic acid