title: Asymmetric synthesis of 3-substituted tetrahydro-2-benzazepines.
abstract: The enantiomerically and diastereomerically pure tricyclic oxazolidine cis-10 was prepared in a five step synthesis starting with 1-bromo-2-iodobenzene. Me3SiCN and allylSiMe3 reacted with cis-10 in the presence of TiCl4 to form the nitrile (3S)-11 and the allyl derivative (3S)-12 with high diastereoselectivity. The hydrogenolytic removal of the chiral auxiliary failed, since the endocyclic benzyl-N-bond was cleaved simultaneously. Therefore the N-(hydroxyethyl)amide of (3S)-12 was transformed into the enamide 27, which was hydrolyzed to afford the secondary amide 28. The enamide strategy to remove the chiral auxiliary from (3S)-11 led to complete racemization due to fast deprotonation in α-position of the cyano moiety. Two pairs of enantiomers 30a-b/ent-30a-b with prototypical σ substituents at the N-atom were prepared. The low σ1 affinity of the tetrahydro-2-benzazepines (ent-30b, Ki = 407 nM) is attributed to the short distance between the two lipophilic aromatic moieties.
authors.affiliation: Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany. wuensch@uni-muenster.de.
authors.forename: Matthias P
authors.initials: MP
authors.lastname: Quick
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
authors.forename: Dirk
authors.initials: D
authors.lastname: Schepmann
authors.forename: Bernhard
authors.initials: B
authors.lastname: Wünsch
mesh_terms: D001552:Benzazepines / Q000138:chemical synthesis* / Q000737:chemistry* / Q000378:metabolism; D060326:Chemistry Techniques, Synthetic; D017480:Receptors, sigma / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D001552:Benzazepines; D017480:Receptors, sigma