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Wu J, Young CM, Watts AA, Slawin AMZ, Boyce GR, Bühl M, Smith AD. Isothiourea-Catalyzed Enantioselective Michael Addition of Malonates to α,β-Unsaturated Aryl Esters. Org Lett 2022; 24:4040-4045. [PMID: 35652512 PMCID: PMC9278409 DOI: 10.1021/acs.orglett.2c01486] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
An enantioselective Michael addition of malonates to α,β-unsaturated para-nitrophenyl esters was achieved using the Lewis basic isothiourea HyperBTM, giving excellent levels of product enantioselectivity (up to >99:1 enantiomeric ratio) in good yields and with complete regioselectivity (>20:1 regioselectivity ratio) in the presence of alternative (phenyl ketone and ethyl ester) Michael acceptors. Density functional theory calculations indicate that N-acylation is rate-limiting. This constitutes a rare example of a highly enantioselective addition of simple, readily available malonates to α,β-unsaturated esters.
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Affiliation(s)
- Jiufeng Wu
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Claire M Young
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Amy A Watts
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Alexandra M Z Slawin
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Gregory R Boyce
- Department of Chemistry and Physics, Florida Gulf Coast University, Fort Myers, Florida 33965, United States
| | - Michael Bühl
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, United Kingdom
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