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Cai I, Malig TC, Kurita KL, Derasp JS, Sirois LE, Hein JE. Investigating the Origin of Epimerization Attenuation during Pd-Catalyzed Cross-Coupling Reactions. ACS Catal 2024; 14:12331-12341. [PMID: 39169902 PMCID: PMC11334108 DOI: 10.1021/acscatal.4c03401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 07/24/2024] [Accepted: 07/24/2024] [Indexed: 08/23/2024]
Abstract
Palladium-catalyzed cross-couplings remain among the most robust methodologies to form carbon-carbon and carbon-heteroatom bonds. In particular, carbon-nitrogen (C-N) couplings (Buchwald-Hartwig aminations) find widespread use in fine chemicals industries. The use of base in these reactions is critical for catalyst activation and proton sequestration. Base selection also plays an important role in process design, as strongly basic conditions can impact sensitive stereocenters and result in erosion of stereochemical purity. Herein we investigate the role of a Pd catalyst in suppressing base-mediated epimerization of a sultam stereocenter during a C-N cross-coupling reaction to access the RORγ inhibitor GDC-0022. Online high-performance liquid chromatography-mass spectrometry (HPLC-MS) was employed to acquire reaction time course profiles and to delineate epimerization behavior, identify decomposition pathways, and monitor Pd-containing species. Our ability to monitor organopalladium complexes in real time by HPLC-MS provided strong evidence that the degree of epimerization was correlated to the Pd speciation in solution. Specifically, Pd(II) complexes were associated with mitigating epimerization of six-membered sultams. Additional studies showed that the suppression of epimerization in the presence of Pd(II) can impact Pd-catalyzed reactions of other substrates such as enolizable ketones, thus providing practical insight on the execution and optimization of such processes.
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Affiliation(s)
- Isabelle Cai
- Department
of Chemistry, The University of British
Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Thomas C. Malig
- Department
of Synthetic Molecule Analytical Chemistry, Genentech, Inc., South
San Francisco, California 94080, United States
| | - Kenji L. Kurita
- Department
of Synthetic Molecule Analytical Chemistry, Genentech, Inc., South
San Francisco, California 94080, United States
| | - Joshua S. Derasp
- Department
of Chemistry, The University of British
Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Lauren E. Sirois
- Department
of Synthetic Molecule Process Chemistry, Genentech, Inc., South San Francisco, California 94080, United States
| | - Jason E. Hein
- Department
of Chemistry, The University of British
Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Department
of Chemistry, University of Bergen, Bergen N-5020, Norway
- Acceleration
Consortium, The University of Toronto, Toronto, Ontario M5G 1X6, Canada
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2
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Raithel AL, Meador WE, Kim TY, Staples RJ, Delcamp JH, Hamann TW. Molecular Switch Cobalt Redox Shuttle with a Tunable Hexadentate Ligand. J Am Chem Soc 2023; 145:1367-1377. [PMID: 36595559 DOI: 10.1021/jacs.2c12017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Strong-field hexadentate ligands were synthesized and coordinated to cobalt metal centers to result in three new low-spin to low-spin Co(III/II) redox couples. The ligand backbone has been modified with dimethyl amine groups to result in redox potential tuning of the Co(III/II) redox couples from -200 to -430 mV versus Fc+/0. The redox couples surprisingly undergo a reversible molecular switch rearrangement from five-coordinate Co(II) to six-coordinate Co(III) despite the ligands being hexadentate. The complexes exhibit modestly faster electron self-exchange rate constants of 2.2-4.2 M-1 s-1 compared to the high-spin to low-spin redox couple [Co(bpy)3]3+/2+ at 0.27 M-1 s-1, which is attributed to the change in spin state being somewhat offset by this coordination switching behavior. The complexes were utilized as redox shuttles in dye-sensitized solar cells with the near-IR AP25 + D35 dye system and exhibited improved photocurrents over the [Co(bpy)3]3+/2+ redox shuttle (19.8 vs 18.0 mA/cm2). Future directions point toward pairing the low-spin to low-spin Co(II/III) tunable series to dyes with significantly more negative highest occupied molecular orbital potentials that absorb into the near-IR where outer sphere redox shuttles have failed to produce efficient dye regeneration.
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Affiliation(s)
- Austin L Raithel
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan48823, United States
| | - William E Meador
- Department of Chemistry and Biochemistry, Coulter Hall, University of Mississippi, University, Mississippi38677, United States
| | - Tea-Yon Kim
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan48823, United States
| | - Richard J Staples
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan48823, United States
| | - Jared H Delcamp
- UES, Inc. Research Scientist, Air Force Research Labs, Materials and Manufacturing Directorate, 2230 Tenth Street B655 R198, WPAFB, Ohio45433-7817, United States
| | - Thomas W Hamann
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, Michigan48823, United States
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3
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Manakin YV, Mironov VS, Bazhenova TA, Yakushev IA, Gilmutdinov IF, Simonov SV, Yagubskii EB. (Et 4N)[W III(DAPBH)(CN) 2], the first pentagonal-bipyramidal W(III) complex with unquenched orbital angular momentum: a novel Ising-type magnetic building block for single-molecule magnets. Chem Commun (Camb) 2023; 59:643-646. [PMID: 36537239 DOI: 10.1039/d2cc05998c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The first pentagonal-bipyramidal tungsten(III) complex (Et4N)[WIII(DAPBH)(CN)2] with a N3O2-type Schiff-base ligand and two apical cyanide groups was synthesized and characterized structurally and magnetically. The complex has a low-spin (S = 1/2) ground state and features unquenched orbital angular momentum ML = ±1 causing very strong Ising-type magnetic anisotropy.
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Affiliation(s)
- Yu V Manakin
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS, Chernogolovka, Russia.
| | - V S Mironov
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS, Chernogolovka, Russia. .,Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics" RAS, Moscow, Russia.
| | - T A Bazhenova
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS, Chernogolovka, Russia.
| | - I A Yakushev
- Kurnakov Institute of General and Inorganic Chemistry, Moscow, Russia.,National Research Center "Kurchatov Institute", Moscow, Russia
| | - I F Gilmutdinov
- Institute of Physics, Kazan Federal University, Kazan, Russia
| | - S V Simonov
- Institute of Solid State Physics, Chernogolovka, Russia
| | - E B Yagubskii
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS, Chernogolovka, Russia.
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4
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Carter C, Kratish Y, Jurca T, Gao Y, Marks TJ. Bis-Ferrocenyl-Pyridinediimine Trinuclear Mixed-Valent Complexes with Metal-Binding Dependent Electronic Coupling: Synthesis, Structures, and Redox-Spectroscopic Characterization. J Am Chem Soc 2020; 142:18715-18729. [DOI: 10.1021/jacs.0c10015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Cole Carter
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208−3113, United States
| | - Yosi Kratish
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208−3113, United States
| | - Titel Jurca
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208−3113, United States
| | - Yanshan Gao
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208−3113, United States
| | - Tobin J. Marks
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208−3113, United States
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5
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Chalkley MJ, Garrido-Barros P, Peters JC. A molecular mediator for reductive concerted proton-electron transfers
via electrocatalysis. Science 2020; 369:850-854. [DOI: 10.1126/science.abc1607] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/24/2020] [Indexed: 12/16/2022]
Abstract
Electrocatalytic approaches to the activation of unsaturated substrates
via reductive concerted proton-electron transfer (CPET) must overcome
competing, often kinetically dominant hydrogen evolution. We introduce the
design of a molecular mediator for electrochemically triggered reductive
CPET through the synthetic integration of a Brønsted acid and a redox
mediator. Cathodic reduction at the cobaltocenium redox mediator
substantially weakens the homolytic nitrogen-hydrogen bond strength of a
Brønsted acidic anilinium tethered to one of the cyclopentadienyl rings. The
electrochemically generated molecular mediator is demonstrated to transform
a model substrate, acetophenone, to its corresponding neutral α-radical via
a rate-determining CPET.
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Affiliation(s)
- Matthew J. Chalkley
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Pablo Garrido-Barros
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jonas C. Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
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Talasila DS, Queensen MJ, Barnes-Flaspoler M, Jurkowski K, Stephenson E, Rabus JM, Bauer EB. Ferrocenium Cations as Catalysts for the Etherification of Cyclopropyl-Substituted Propargylic Alcohols: Ene-yne Formation and Mechanistic Insights. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Deva Saroja Talasila
- University of Missouri - St. Louis; Department of Chemistry and Biochemistry; One University Boulevard 63121 St. Louis MO USA
| | - Matthew J. Queensen
- University of Missouri - St. Louis; Department of Chemistry and Biochemistry; One University Boulevard 63121 St. Louis MO USA
| | - Michael Barnes-Flaspoler
- University of Missouri - St. Louis; Department of Chemistry and Biochemistry; One University Boulevard 63121 St. Louis MO USA
| | - Kellsie Jurkowski
- University of Missouri - St. Louis; Department of Chemistry and Biochemistry; One University Boulevard 63121 St. Louis MO USA
| | - Evan Stephenson
- University of Missouri - St. Louis; Department of Chemistry and Biochemistry; One University Boulevard 63121 St. Louis MO USA
| | - Jordan M. Rabus
- University of Missouri - St. Louis; Department of Chemistry and Biochemistry; One University Boulevard 63121 St. Louis MO USA
| | - Eike B. Bauer
- University of Missouri - St. Louis; Department of Chemistry and Biochemistry; One University Boulevard 63121 St. Louis MO USA
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