A total synthesis of javaberine A was achieved through a lithium amide-mediated intramolecular hydroamination of an N-allyl aminoalkene. The desired hydroamination was accomplished using an excess of i-PrNH with a substoichiometric amount of n-BuLi. Using an excess of both n-BuLi and i-PrNH led to tandem cyclization, however, resulting in the construction of a tricyclic structure through the formation of one C-N and two C-C bonds in a single operation. Additionally, epimerization of the H8-H14 cis-benzyl tetrahydroisoquinoline to the trans isomer was achieved via β-elimination followed by intramolecular hydroamination.
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http://dx.doi.org/10.1248/cpb.c24-00693 | DOI Listing |
Org Lett
December 2024
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.
Multisubstituted piperidines are prevalent units in pharmaceuticals. Herein, a photodriven anti-Markovnikov hydroaminative cyclization of a ()/()-isomeric mixture of trisubstituted alkenes using the lactate-derived -symmetric arylthiol catalyst was developed for the synthesis of -2,3-disubstituted piperidines and azepane in high diastereoselectivity and good yields. The origin of diastereoselectivity and the observed different hydroamination rate of alkene with different configurations were elucidated by the experimental and computational investigation.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
December 2024
Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts.
A total synthesis of javaberine A was achieved through a lithium amide-mediated intramolecular hydroamination of an N-allyl aminoalkene. The desired hydroamination was accomplished using an excess of i-PrNH with a substoichiometric amount of n-BuLi. Using an excess of both n-BuLi and i-PrNH led to tandem cyclization, however, resulting in the construction of a tricyclic structure through the formation of one C-N and two C-C bonds in a single operation.
View Article and Find Full Text PDFOrg Lett
November 2024
Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada.
Despite major advances, intramolecular alkene hydroamination reactions often face limitations. Herein, a redox-enabled process featuring oxidation of an amine to a hydroxylamine, a concerted hydroamination step, followed by catalytic reduction of -oxide is shown to be broadly applicable. Catalyst screening and optimization showed that a KOsO(OH)-pinacol complex rapidly and chemoselectively reduces the -oxide cycloadduct in the presence of hydroxylamine and dimethyl sulfoxide.
View Article and Find Full Text PDFJ Org Chem
November 2024
Departamento de Química Orgánica y Química Inorgánica, Instituto de Investigación Andrés M. del Río (IQAR), Facultad de Farmacia, Universidad de Alcalá, Alcalá de Henares, 28805 Madrid, Spain.
A copper-catalyzed intramolecular synthesis of 3-alkenyl-2-indazoles from 2-alkynylazobenzenes is described. The reaction proceeds in a single step via C-N bond formation and a subsequent 1,2-hydride shift, affording products in high yields. DFT calculations suggest the 1,2-hydride shift as the rate-determining step.
View Article and Find Full Text PDFJ Org Chem
November 2024
CICA, Centro Interdisciplinar de Química e Bioloxía and Departamento de Química, Universidade da Coruña, 15071 A Coruña, Spain.
Pyrroles, privileged structural motifs in drug and material science, have been synthesized by indium(III)-catalyzed intramolecular cyclization of homopropargyl azides. This methodology exhibits a broad substrate scope, providing substituted pyrroles and bispyrroles in good yields. Furthermore, an atom-economical sequential method for the synthesis of benzo[]indoles has been discovered from azido-diynes using InCl as catalyst.
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