title: Studies Directed toward the Synthesis of Aspidophytine: Construction of Its Perhydroquinoline Core.
abstract: We have developed an efficient route for the synthesis of the perhydroquinoline core of the indole alkaloid aspidophytine (2), starting from commercially available and inexpensive 3-acetylpyridine. This densely functionalized perhydroquinoline core displays four contiguous stereocenters including an all-carbon quaternary center. The synthetic sequence features a highly effective Diels-Alder reaction using a carbamate-substituted siloxy diene accompanied by a spontaneous intramolecular substitution of the newly formed 3°-alkyl bromide with a carbamate group. The installation of the electron-rich aniline moiety was accomplished via a TBSOTf-mediated intramolecular aza-Michael reaction, and the relative stereochemistry of the aza-Michael product (30) was confirmed by X-ray crystallographic analysis. Among the useful transformations that were developed through this study is a highly enantioselective Diels-Alder reaction of a versatile cyclic carbamate siloxy diene.
authors.affiliation: Department of Chemistry, University of Chicago , 5735 South Ellis Avenue Chicago, Illinois 60637, United States.
authors.forename: Yunus E
authors.initials: YE
authors.lastname: Türkmen
authors.affiliation: Department of Chemistry, University of Chicago , 5735 South Ellis Avenue Chicago, Illinois 60637, United States.
authors.forename: Michel
authors.initials: M
authors.lastname: Gravel
authors.affiliation: Department of Chemistry, University of Chicago , 5735 South Ellis Avenue Chicago, Illinois 60637, United States.
authors.forename: Viresh H
authors.initials: VH
authors.lastname: Rawal
mesh_terms: D066241:Carbon-13 Magnetic Resonance Spectroscopy; D018360:Crystallography, X-Ray; D061565:Cycloaddition Reaction; D006576:Heterocyclic Compounds, 4 or More Rings / Q000138:chemical synthesis* / Q000737:chemistry; D026121:Indole Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D066244:Proton Magnetic Resonance Spectroscopy; D011804:Quinolines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism
chemical_list: D006576:Heterocyclic Compounds, 4 or More Rings; D026121:Indole Alkaloids; D011804:Quinolines; C476906:aspidophytine