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Jones B, Solon P, Popescu MV, Du JY, Paton R, Smith MD. Catalytic Enantioselective 6π Photocyclization of Acrylanilides. J Am Chem Soc 2022; 145:171-178. [PMID: 36571763 PMCID: PMC9837842 DOI: 10.1021/jacs.2c09267] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Controlling absolute stereochemistry in catalytic photochemical reactions is generally challenging owing to high rates of background reactivity. Successful strategies broadly rely on selective excitation of the reaction substrate when associated with a chiral catalyst. Recent studies have demonstrated that chiral Lewis acid complexes can enable selective energy transfer from a photosensitizer to facilitate enantioselective triplet state reactions. Here, we apply this approach to the enantioselective catalysis of a 6π photocyclization through the design of an iridium photosensitizer optimized to undergo energy transfer to a reaction substrate only in the presence of a chiral Lewis acid complex. Among a group of iridium(III) sensitizers, enantioselectivity and yield closely correlate with photocatalyst triplet energy within a narrow window enabled by a modest reduction in substrate triplet energy upon binding a scandium/ligand complex. These results demonstrate that photocatalyst tuning offers a means to suppress background reactivity and improve enantioselectivity in photochemical reactions.
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Affiliation(s)
- Benjamin
A. Jones
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K.
| | - Pearse Solon
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K.
| | - Mihai V. Popescu
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K.,Department
of Chemistry, Colorado State University, 1301 Center Avenue, Ft. Collins, Colorado 80523-1872, United States
| | - Ji-Yuan Du
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K.
| | - Robert Paton
- Department
of Chemistry, Colorado State University, 1301 Center Avenue, Ft. Collins, Colorado 80523-1872, United States,
| | - Martin D. Smith
- Chemistry
Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, U.K.,
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Mei GJ, Wong JJ, Zheng W, Nangia AA, Houk K, Lu Y. Rational design and atroposelective synthesis of N–N axially chiral compounds. Chem 2021. [DOI: 10.1016/j.chempr.2021.07.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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