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Frolov AI, Chuchvera YO, Ostapchuk EN, Druzhenko TV, Volochnyuk DM, Ryabukhin SV. Toward a Chemical Constructor: A Lego-Like Approach for Formal α-Alkylation of Cyclic Ketones. J Org Chem 2024. [PMID: 38764429 DOI: 10.1021/acs.joc.3c02628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
A conceptual strategy for a formal α-alkylation of α-methylene ketones was developed. Diverse 1° and 2° alkyl substituents were generated in the α-position of various ketones via synthesis of enaminone (step 1) and treatment with organomagnesium (step 2) with subsequent catalytic hydrogenation (step 3, 1° alkyl) or organocopper reagents (step 4, 2° alkyl). Tolerance toward ester, Boc-protected amine, and α-fluoro-substituted ketone moieties was demonstrated. The suitability of the method for late-stage natural product modification was shown.
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Affiliation(s)
- Andriy I Frolov
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
| | | | - Eugeniy N Ostapchuk
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
| | - Tetiana V Druzhenko
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
| | - Dmytro M Volochnyuk
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 5 Akademik Kuhar Street, 02660 Kyiv, Ukraine
| | - Serhiy V Ryabukhin
- Enamine Limited, 78 Winston Churchill Street, 02094 Kyiv, Ukraine
- Taras Shevchenko National University of Kyiv, 60 Volodymyrska Street, 01601 Kyiv, Ukraine
- Institute of Organic Chemistry, National Academy of Sciences of Ukraine, 5 Akademik Kuhar Street, 02660 Kyiv, Ukraine
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Šegina J, Ciber L, Brodnik H, Požgan F, Svete J, Štefane B, Grošelj U. Synthesis of Six-Membered N-Heterocyclic Carbene Precursors Based on Camphor. Molecules 2023; 28:7973. [PMID: 38138463 PMCID: PMC10745536 DOI: 10.3390/molecules28247973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 11/29/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
The endo- and exo-N-heterocyclic carbene precursors based on camphor were prepared diastereoselectively in five synthetic steps starting from (1S)-(+)-ketopinic acid. The obtained N-heterocyclic carbene precursors were investigated in an asymmetric benzoin reaction. All new compounds were fully characterized, and the absolute configurations were determined via X-ray diffraction and NOESY measurements.
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Affiliation(s)
| | | | | | | | | | | | - Uroš Grošelj
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna Pot 113, 1000 Ljubljana, Slovenia; (J.Š.); (L.C.); (F.P.); (J.S.); (B.Š.)
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Conformational and Supramolecular Aspects in Chirality of Flexible Camphor-Containing Schiff Base as an Inducer of Helical Liquid Crystals. Molecules 2023; 28:molecules28052388. [PMID: 36903637 PMCID: PMC10005677 DOI: 10.3390/molecules28052388] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
The experimental and theoretical study of influence of the conformational state and association on the chirality of the stereochemically nonrigid biologically active bis-camphorolidenpropylenediamine (CPDA) and its ability to induce the helical mesophase of alkoxycyanobiphenyls liquid-crystalline binary mixture was carried out. On the basis of quantum-chemical simulation of the CPDA structure, four relatively stable conformers were detected. A comparison of the calculated and experimental electronic circular dichroism (ECD) and 1H, 13C, 15N NMR spectra, as well as specific optical rotation and dipole moments, allowed to establish the most probable trans-gauche conformational state (tg) of dicamphorodiimine and CPDA dimer with a predominantly mutually parallel arrangement of molecular dipoles. The induction of helical phases in LC mixtures based on cyanobiphenyls and bis-camphorolidenpropylenediamine was studied by polarization microscopy. The clearance temperatures and the helix pitch of the mesophases were measured. The helical twisting power (HTP) was calculated. The decrease in HTP with increasing dopant concentration was shown to be connected with the CPDA association process in the LC phase. The effect of camphor-containing chiral dopants of various structures on nematic LCs was compared. The values of the permittivity and birefringence components of the CPDA solutions in CB-2 were measured experimentally. A strong effect of this dopant on the anisotropic physical properties of the induced chiral nematic was established. A significant decrease in the dielectric anisotropy was associated with the 3D compensation of the LC dipoles during the formation of the helix.
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Ričko S, Požgan F, Štefane B, Svete J, Golobič A, Grošelj U. Stereodivergent Synthesis of Camphor-Derived Diamines and Their Application as Thiourea Organocatalysts. Molecules 2020; 25:molecules25132978. [PMID: 32610466 PMCID: PMC7412124 DOI: 10.3390/molecules25132978] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/26/2020] [Accepted: 06/27/2020] [Indexed: 11/16/2022] Open
Abstract
A series of 18 regio- and stereo-chemically diverse chiral non-racemic 1,2-, 1,3-, and 1,4-diamines have been synthesized from commercial (1S)-(+)-ketopinic acid and (1S)-(+)-10-camphorsulfonic acid. The structures of the diamines are all based on the d-(+)-camphor scaffold and feature isomeric diversity in terms of regioisomeric attachment of the primary and the tertiary amine function and the exo/endo-isomerism. Diamines were transformed into the corresponding noncovalent bifunctional thiourea organocatalysts, which have been evaluated for catalytic activity in the conjugative addition of 1,3-dicarbonyl nucleophiles (dimethyl malonate, acetylacetone, and dibenzoylmethane) to trans-β-nitrostyrene. The highest enantioselectivity was achieved in the reaction with acetylacetone as nucleophile using endo-1,3-diamine derived catalyst 52 (91.5:8.5 er). All new organocatalysts 48-63 have been fully characterized. The structures and the absolute configurations of eight intermediates and thiourea derivative 52 were also determined by X-ray diffraction.
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Carvalho MFNN, Ferreira MJ, Knittel ASO, Oliveira MDC, Costa Pessoa J, Herrmann R, Wagner G. Strecker degradation of amino acids promoted by a camphor-derived sulfonamide. Beilstein J Org Chem 2016; 12:732-44. [PMID: 27340465 PMCID: PMC4902088 DOI: 10.3762/bjoc.12.73] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 03/24/2016] [Indexed: 11/23/2022] Open
Abstract
A camphor-derived sulfonimine with a conjugated carbonyl group, oxoimine 1 (O2SNC10H13O), reacts with amino acids (glycine, L-alanine, L-phenylalanine, L-leucine) to form a compound O2SNC10H13NC10H14NSO2 (2) which was characterized by spectroscopic means (MS and NMR) and supported by DFT calculations. The product, a single diastereoisomer, contains two oxoimine units connected by a –N= bridge, and thus has a structural analogy to the colored product Ruhemann´s purple obtained by the ninhydrin reaction with amino acids. A plausible reaction mechanism that involves zwitterions, a Strecker degradation of an intermediate imine and water-catalyzed tautomerizations was developed by means of DFT calculations on potential transition states.
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Affiliation(s)
- M Fernanda N N Carvalho
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001 Lisboa, Portugal
| | - M João Ferreira
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001 Lisboa, Portugal
| | - Ana S O Knittel
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001 Lisboa, Portugal
| | - Maria da Conceição Oliveira
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001 Lisboa, Portugal
| | - João Costa Pessoa
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1049-001 Lisboa, Portugal
| | - Rudolf Herrmann
- Institut für Physik, Universität Augsburg, Universitätsstr. 2, 86159 Augsburg, Germany
| | - Gabriele Wagner
- University of Chester, Faculty of Science and Engineering, Department of Natural Sciences, Thornton Science Park, Pool Lane, Ince, Chester, CH2 4NU, UK
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Shokova EA, Kim JK, Kovalev VV. Camphor and its derivatives. Unusual transformations and biological activity. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2016. [DOI: 10.1134/s1070428016040011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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