The first enantioselective Pictet-Spengler reaction of acyclic α-ketoesters with tryptamines has been developed. Excellent yields and enantioselectivity were obtained for the reaction using chiral imidazoline-phosphoric acid catalysts. Density functional theory calculations suggested possible transition states that explain the origin of chiral induction. This process provides an efficient route for the synthesis of tetrahydro-β-carboline derivatives.
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http://dx.doi.org/10.1021/acs.orglett.1c04316 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, People's Republic of China.
The bisbenzylisoquinoline alkaloids (bisBIAs) have attracted tremendous attention from the synthetic community due to their diverse and intriguing biological activities. Herein, we report the convergent and modular chemoenzymatic syntheses of eight bisBIAs bearing various substitutes and linkages in 5-7 steps. The gram-scale synthesis of various well-designed enantiopure benzylisoquinoline monomers was accomplished through an enzymatic stereoselective Pictet-Spengler reaction, followed by regioselective enzymatic methylation or chemical functionalization in a sequential one-pot process.
View Article and Find Full Text PDFChem Sci
March 2024
Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
A catalyst possessing a broad substrate scope, in terms of both turnover and enantioselectivity, is sometimes called "general". Despite their great utility in asymmetric synthesis, truly general catalysts are difficult or expensive to discover traditional high-throughput screening and are, therefore, rare. Existing computational tools accelerate the evaluation of reaction conditions from a pre-defined set of experiments to identify the most general ones, but cannot generate entirely new catalysts with enhanced substrate breadth.
View Article and Find Full Text PDFACS Catal
February 2023
Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States.
Enantioselective oxa-Pictet-Spengler reactions of tryptophol with aldehydes proceed under weakly acidic conditions utilizing a combination of two catalysts, an indoline HCl salt and a bisthiourea compound. Mechanistic investigations revealed the roles of both catalysts and confirmed the involvement of oxocarbenium ion intermediates, ruling out alternative scenarios. A stereochemical model was derived from density functional theory calculations, which provided the basis for the development of a highly enantioselective stereodivergent variant with racemic tryptophol derivatives.
View Article and Find Full Text PDFBioorg Chem
August 2023
School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea. Electronic address:
Herein, atropisomeric 8-aryltetrahydroisoquinolines have been synthesized and biologically evaluated. Based on our structure-activity relationship study, a highly bioactive racemic compound has been produced, and it exhibited high antiproliferative activities against various cancer cell lines, including docetaxel-resistant breast cancer cell lines. Each enantiomer can be synthesized in an enantioselective manner by employing the chiral phosphoric acid-catalyzed atroposelective Pictet-Spengler cyclization.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2023
Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH, 5304, 1015, Lausanne, Switzerland.
We report herein an asymmetric Pictet-Spengler reaction of α-ketoesters. In the presence of a catalytic amount of simple alanine-derived squaramide and p-nitrobenzoic acid, reaction of tryptamines with methyl 2-oxoalkanoates afforded the corresponding 1-alkyl-1-methoxycarbonyl tetrahydro-β-carbolines (THBCs) in high yields and ee values. A primary kinetic isotope effect (KIE=4.
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