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Jiao Z, Jaunich KT, Tao T, Gottschall O, Hughes MM, Turlik A, Schuppe AW. Unified Approach to Deamination and Deoxygenation Through Isonitrile Hydrodecyanation: A Combined Experimental and Computational Investigation. Angew Chem Int Ed Engl 2024; 63:e202405779. [PMID: 38619535 DOI: 10.1002/anie.202405779] [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: 03/25/2024] [Revised: 04/13/2024] [Accepted: 04/15/2024] [Indexed: 04/16/2024]
Abstract
Herein, we describe a general hydrodefunctionalization protocol of alcohols and amines through a common isonitrile intermediate. To cleave the relatively inert C-NC bond, we leveraged dual hydrogen atom transfer (HAT) and photoredox catalysis to generate a nucleophilic boryl radical, which readily forms an imidoyl radical intermediate from the isonitrile. Rapid β-scission then accomplishes defunctionalization. This method has been applied to the hydrodefunctionalization of both amine and alcohol-containing pharmaceuticals, natural products, and biomolecules. We extended this approach to the reduction of carbonyls and olefins to their saturated counterparts, as well as the hydrodecyanation of alkyl nitriles. Both experimental and computational studies demonstrate a facile β-scission of the imidoyl radical, and reconcile differences in reactivity between nitriles and isonitriles within our protocol.
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Affiliation(s)
- Ziqi Jiao
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Kyle T Jaunich
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Thomas Tao
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Olivia Gottschall
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Maxwell M Hughes
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
| | - Aneta Turlik
- Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, NY, 12866, USA
| | - Alexander W Schuppe
- Department of Chemistry, Vanderbilt University, 1234 Stevenson Center Ln, Nashville, TN, 37240, USA
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Schneider J, Häring AP, Waldvogel SR. Electrochemical Dehydration of Dicarboxylic Acids to Their Cyclic Anhydrides. Chemistry 2024; 30:e202400403. [PMID: 38527230 DOI: 10.1002/chem.202400403] [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: 01/30/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 03/27/2024]
Abstract
An intramolecular electrochemical dehydration reaction of dicarboxylic acids to their cyclic anhydrides is presented. This electrolysis allows dicarboxylic acids as naturally abundant, inexpensive, safe, and readily available starting materials to be transformed into carboxylic anhydrides under mild reaction conditions. No conventional dehydration reagent is required. The obtained cyclic anhydrides are highly valuable reagents in organic synthesis, and in this report, we use them in-situ for acylation reactions of amines to synthesize amides. This work is part of the recent progress in electrochemical dehydration, which - in contrast to electrochemical dehydrogenative reactions for example - is an underexplored field of research. The reaction mechanism was investigated by 18O isotope labeling, revealing the formation of sulfate by electrochemical oxidation and hydrolysis of the thiocyanate-supporting electrolyte. This transformation is not a classical Kolbe electrolysis, because it is non-decarboxylative, and all carbon atoms of the carboxylic acid starting material are contained in the carboxylic anhydride. In total, 20 examples are shown with NMR yields up to 71 %.
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Affiliation(s)
- Johannes Schneider
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Andreas P Häring
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Siegfried R Waldvogel
- Department of Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany
- Karlsruhe Institut für Technologie, Kaiserstraße 12, 76131, Karlsruhe, Germany
- Max-Planck-Institute for Chemical Energy Conversion (MPI CEC), Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
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Marchese AD, Dorsheimer JR, Rovis T. Photoredox-Catalyzed Generation of Tertiary Anions from Primary Amines via a Radical Polar Crossover. Angew Chem Int Ed Engl 2024; 63:e202317563. [PMID: 38189622 PMCID: PMC10873470 DOI: 10.1002/anie.202317563] [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: 11/17/2023] [Indexed: 01/09/2024]
Abstract
A method for the generation of tertiary carbanions via a deaminative radical-polar crossover is reported using redox active imines from α-tertiary primary amines. A variety of benzylic amines and amino esters can be used in this approach, with the latter engaging in a novel "aza-Reformatsky" reaction. Electronic trends correlate the stability of the resulting carbanion with reaction efficiency. The anions can be trapped with different electrophiles including aldehydes, ketones, imines, Michael acceptors, and H2 O/D2 O. Selective anion formation can be achieved in the presence of another equivalent or more acidic C-H bond in both an inter- and intramolecular fashion. Mechanistic studies suggest the intermediacy of a discrete carbanion intermediate.
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Affiliation(s)
- Austin D. Marchese
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Julia R. Dorsheimer
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Tomislav Rovis
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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