title: Stereochemical Course of Deprotonation-Acylation of N-Boc- and N-Carbamoyl-2-cyano-6-methylpiperidines.
abstract: The stereochemical course of electrophilic substitution of α-nitrile metallocarbanions generated by deprotonation from N-Boc- and N-carbamoyl-2-cyano-6-methylpiperidines was investigated. Deprotonation in the presence of an electrophile taking advantage of the high acidity of α-nitrile protons allowed examination of the effects of a chelating group on the nitrogen atom, a countercation, and the reactivity of an electrophile on the steric course. Analyses of reactions using aroyl chlorides and methyl iodide revealed the following: (1) the substitution reactions basically proceed with retention of configuration, (2) the extent of an inversion product increases with decreasing chelating ability of the N-substituent and with increasing leaving ability (ionic character) of a countercation (Li, Na, K) of the anionic species, and (3) the use of a more reactive electrophile results in an increase of the retention product.
authors.affiliation: Department of Synthetic Organic Chemistry, Institute of Biomedical & Health Sciences, Hiroshima University , 1-2-3 Kasumi, Minami-Ku, Hiroshima 734-8553, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Kotomori
authors.affiliation: Department of Synthetic Organic Chemistry, Institute of Biomedical & Health Sciences, Hiroshima University , 1-2-3 Kasumi, Minami-Ku, Hiroshima 734-8553, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: Pharmaceutical Sciences at Kagawa Campus, Tokushima Bunri University , 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Kawahata
authors.affiliation: Pharmaceutical Sciences at Kagawa Campus, Tokushima Bunri University , 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Department of Synthetic Organic Chemistry, Institute of Biomedical & Health Sciences, Hiroshima University , 1-2-3 Kasumi, Minami-Ku, Hiroshima 734-8553, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Takeda