title: Stereocontrolled ring-opening of a hindered sulfamidate with nitrogen-containing aromatic heterocycles: synthesis of chiral quaternary imidazole derivatives.
abstract: This paper explores the role of a hindered cyclic sulfamidate derived from α-methylisoserine as an electrophile in a nucleophilic displacement reaction with nitrogen-containing aromatic heterocycles. Several imidazoles and pyrazole were tested as nucleophiles in the absence of an additional base to give the corresponding ring-opening compounds. We show that the process takes place by inversion of the configuration of the quaternary electrophilic center, retaining the enantiomeric excess of the starting sulfamidate. This reaction opens the way to obtain important quaternary imidazole derivatives such as an innovative type of bis-amino acid related to histidinoalanine and a novel α,α-disubstituted β-amino acid (β(2,2)-amino acid).
authors.affiliation: Departamento de Química, Universidad de La Rioja, Centro de Investigación en Síntesis Química, UA-CSIC, E-26006 Logroño, Spain.
authors.forename: Lara
authors.initials: L
authors.lastname: Mata
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Jiménez-Osés
authors.forename: Alberto
authors.initials: A
authors.lastname: Avenoza
authors.forename: Jesús H
authors.initials: JH
authors.lastname: Busto
authors.forename: Jesús M
authors.initials: JM
authors.lastname: Peregrina