One-Pot Formation of Piperidine- and Pyrrolidine-Substituted Pyridinium Salts via Addition of 5-Alkylaminopenta-2,4-dienals to <i>N</i>-Acyliminium Ions: Application to the Synthesis of (±)-Nicotine and Analogs
triflate, followed by dehydrative cyclization, allowed the formation of pyridiniumsalts substituted at their 3-position by a five- or six-membered nitrogen heterocycle. Subsequent N-dealkylation of the pyridinium moiety and deprotection of the secondary amine or reduction of the carbamate function led to (±)-nicotine and analogs.
Superacid promoted reactions of N-acyliminium salts and evidence for the involvement of superelectrophiles
作者:Yiliang Zhang、Daniel J. DeSchepper、Thomas M. Gilbert、Kiran Kumar S. Sai、Douglas A. Klumpp
DOI:10.1039/b708760h
日期:——
Experimental and theoretical studies suggest the involvement of dicationic, superelectrophilic N-acyliminium ions in conversions catalyzed by superacids.
Enantioselective, Thiourea-Catalyzed Intermolecular Addition of Indoles to Cyclic N-Acyl Iminium Ions
作者:Emily A. Peterson、Eric N. Jacobsen
DOI:10.1002/anie.200902420
日期:——
Fair game for indoles, N‐acyl iminiumion intermediates underwent intermolecularaddition by these nucleophiles under the catalysis of a chiral thiourea Schiff base derivative. A variety of functionalized indole frameworks were assembled with high enantioselectivity from simple precursors by this method (see scheme; TMS=trimethylsilyl; R=H, Me, vinyl, OMe, F, Cl, Br; R1=benzyl, methyl; n=1,2).
Guzman, Angel; Romero, Moises; Muchowski, Joseph M., Canadian Journal of Chemistry, 1990, vol. 68, # 5, p. 791 - 794
作者:Guzman, Angel、Romero, Moises、Muchowski, Joseph M.
DOI:——
日期:——
One-pot synthesis of pyrrolidino- and piperidinoquinolinones by three-component aza-Diels–Alder reactions of in situ generated N-arylimines and cyclic enamides
作者:Wenxue Zhang、Yisi Dai、Xuerui Wang、Wei Zhang
DOI:10.1016/j.tetlet.2011.09.021
日期:2011.11
An efficient synthesis of hexahydropyrrolo[3,2-c]quinolin-2-ones and hexahydropyridino[3,2-c]quinolin-2-ones has been developed in moderate to high yields by one-pot two-step aza-Diels-Alder reactions of N-arylimines, formed in situ from anilines and benzaldehydes, with cyclic enamides, formed in situ from 5-hydroxypyrrolidin-2-ones and 6-hydroxypiperidin-2-ones by BF3 center dot OEt2-promoted dehydration in dichloromethane at room temperature. The hexahydropyrrolo[3,2-c]quinolin-2-ones were formed as a single exo-stereoisomer in most cases and hexahydropyridino[3,2-c]quinolin-2-ones were formed as a mixture of exo- and endo-isomers favoring the endo-diastereomer. (C) 2011 Elsevier Ltd. All rights reserved.