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Zhang G, Favela D, Chow WL, Iyer RN, Pell AJ, Olson DE. Synthesis of Tertiary Amines through Extrusive Alkylation of Carbamates. Org Lett 2022; 24:6208-6212. [PMID: 35972395 PMCID: PMC9420822 DOI: 10.1021/acs.orglett.2c02516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Basic amines are key elements of many biologically active natural products and pharmaceuticals. Given their inherent reactivity, it is often necessary to protect basic amines during target-directed synthesis, which results in wasteful protection/deprotection sequences. We report a step-economical approach enabling the protection of secondary amines as carbamates prior to their conversion to tertiary amines via the formal extrusion of CO2. This method is applied to the synthesis of iboga alkaloids (±)-conodusine A and (±)-conodusine B.
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Affiliation(s)
- Guoliang Zhang
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - David Favela
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Winston L Chow
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Rishab N Iyer
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Alexander J Pell
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - David E Olson
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
- Department of Biochemistry & Molecular Medicine, School of Medicine, University of California, Davis, 2700 Stockton Blvd., Suite 2102, Sacramento, California 95817, United States
- Center for Neuroscience, University of California, Davis, 1544 Newton Ct., Davis, California 95618, United States
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Shennan BDA, Berheci D, Crompton JL, Davidson TA, Field JL, Williams BA, Dixon DJ. Branching out: redox strategies towards the synthesis of acyclic α-tertiary ethers. Chem Soc Rev 2022; 51:5878-5929. [PMID: 35770619 DOI: 10.1039/d1cs00669j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Acyclic α-tertiary ethers represent a highly prevalent functionality, common to high-value bioactive molecules, such as pharmaceuticals and natural products, and feature as crucial synthetic handles in their construction. As such their synthesis has become an ever-more important goal in synthetic chemistry as the drawbacks of traditional strong base- and acid-mediated etherifications have become more limiting. In recent years, the generation of highly reactive intermediates via redox approaches has facilitated the synthesis of highly sterically-encumbered ethers and accordingly these strategies have been widely applied in α-tertiary ether synthesis. This review summarises and appraises the state-of-the-art in the application of redox strategies enabling acyclic α-tertiary ether synthesis.
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Affiliation(s)
- Benjamin D A Shennan
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Diana Berheci
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Jessica L Crompton
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Timothy A Davidson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Joshua L Field
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Benedict A Williams
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Darren J Dixon
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
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