title: Fully diastereoselective synthesis of polysubstituted, functionalized piperidines and decahydroquinolines based on multicomponent reactions catalyzed by cerium(IV) ammonium nitrate.
abstract: The cerium(IV) ammonium nitrate (CAN)-catalyzed, three-component reaction between primary amines, β-dicarbonyl compounds, and α,β-unsaturated aldehydes in ethanol heated to reflux, constitutes a general, one-pot synthesis of 1,4-dihydropyridines. Their reduction with sodium triacetoxyborohydride furnished piperidine derivatives bearing up to five substituents with full diastereoselectivity in a hitherto inaccessible stereochemical arrangement. The reaction proceeded with no significant loss of enantiomeric purity under mild reduction conditions that are compatible with several functional groups that are normally sensitive to reduction. Octahydroquinolin-5-one derivatives, which were prepared by a modified version of the initial multicomponent reaction, were not suitable substrates for the sodium triacetoxyborohydride mediated reduction, but they were transformed into the corresponding decahydroquinolines, including a precursor of the amphibian alkaloid pumiliotoxin C, by catalytic hydrogenation under a variety of conditions.
authors.affiliation: Departmento de Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad Complutense, Plaza de Ramón y Cajal sn, 28040 Madrid (Spain), Fax: (+34) 91-3941822.
authors.forename: Padmakar A
authors.initials: PA
authors.lastname: Suryavanshi
authors.forename: Vellaisamy
authors.initials: V
authors.lastname: Sridharan
authors.forename: Swarupananda
authors.initials: S
authors.lastname: Maiti
authors.forename: J Carlos
authors.initials: JC
authors.lastname: Menéndez
mesh_terms: D000588:Amines / Q000737:chemistry*; D002563:Cerium / Q000737:chemistry*; D015394:Molecular Structure; D009566:Nitrates / Q000737:chemistry*; D010880:Piperidines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000588:Amines; D009566:Nitrates; D010880:Piperidines; C532772:cerium(IV) ammonium nitrate; D002563:Cerium; C032727:piperidine
keywords: alkaloids; diastereoselectivity; multicomponent reactions; nitrogen heterocycles; piperidines