title: Highly diastereoselective cyanation of methyl ketimines obtained from (R)-glyceraldehyde.
abstract: [reaction: see text] Addition of trimethylsilyl cyanide to ketimines derived from (R)-2,2-dimethyl-1,3-dioxolan-4-yl methyl ketone to generate a quaternary stereocenter has been achieved with high yields and excellent diastereoselectivity. The stereoselectivity was found to be temperature and solvent dependent. The beta-hydroxy-alpha-amino nitrile of syn configuration was the major compound in kinetically controlled reactions, whereas the anti stereoisomer was obtained in excess in thermodynamically controlled reactions. Double stereodifferentiation under kinetic control conditions was successful, and the cyanation reaction occurred with complete syn diastereoselectivity using the matched pair. The versatility of the resulting amino nitrile as a synthetic intermediate was tested by performing the synthesis of orthogonally protected (R)-(2-aminomethyl)alanine.
authors.affiliation: Departamento de Química Orgánica, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, E-50009 Zaragoza, Spain.
authors.forename: Ramón
authors.initials: R
authors.lastname: Badorrey
authors.forename: Carlos
authors.initials: C
authors.lastname: Cativiela
authors.forename: María D
authors.initials: MD
authors.lastname: Díaz-de-Villegas
authors.forename: Roberto
authors.initials: R
authors.lastname: Díez
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Galbiati
authors.forename: José A
authors.initials: JA
authors.lastname: Gálvez
mesh_terms: D003486:Cyanides / Q000737:chemistry*; D005985:Glyceraldehyde / Q000737:chemistry*; D007097:Imines / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D003486:Cyanides; D007097:Imines; D005985:Glyceraldehyde