1
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Nilova A, Mannchen MD, Noel AN, Semenova E, Grenning AJ. Vicinal stereocenters via asymmetric allylic alkylation and Cope rearrangement: a straightforward route to functionally and stereochemically rich heterocycles. Chem Sci 2023; 14:2755-2762. [PMID: 36908968 PMCID: PMC9993902 DOI: 10.1039/d2sc07021a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/13/2023] [Indexed: 02/16/2023] Open
Abstract
An asymmetric allylic alkylation/Cope rearrangement (AAA/[3,3]) capable of stereoselectively constructing vicinal stereocenters has been developed. Strategically integrated 4-methylation on the 3,3-dicyano-1,5-diene controls stereoselectivity and drives Cope rearrangement equilibrium in the forward direction. The AAA/[3,3] sequence rapidly converts abundant achiral and racemic starting materials into valuable (hetero)cycloalkane building blocks bearing significant functional and stereochemical complexity, highlighting the value of (hetero)cyclohexylidenemalononitriles as launching points for complex heterocycle synthesis. On this line, the resulting alkylidenemalononitrile moiety can be readily converted into amides via Hayashi-Lear amidation to ultimately yield amido-piperidines, tropanes, and related scaffolds with 3-5 stereocenters and drug-like functionality.
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Affiliation(s)
- Aleksandra Nilova
- Department of Chemistry, University of Florida PO Box 117200 Gainesville 32611 FL USA
| | - Michael D Mannchen
- Department of Chemistry, University of Florida PO Box 117200 Gainesville 32611 FL USA
| | - Abdias N Noel
- Department of Chemistry, University of Florida PO Box 117200 Gainesville 32611 FL USA
| | - Evgeniya Semenova
- Department of Chemistry, University of Florida PO Box 117200 Gainesville 32611 FL USA
| | - Alexander J Grenning
- Department of Chemistry, University of Florida PO Box 117200 Gainesville 32611 FL USA
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2
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De S, Tomiczek BM, Yang Y, Ko K, Ghiviriga I, Roitberg A, Grenning AJ. Diastereoselective Indole-Dearomative Cope Rearrangements by Compounding Minor Driving Forces. Org Lett 2022; 24:3726-3730. [PMID: 35576941 PMCID: PMC10112279 DOI: 10.1021/acs.orglett.2c01381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reported herein is the discovery of a diastereoselective indole-dearomative Cope rearrangement. A suite of minor driving forces promote dearomatization: (i) steric congestion in the starting material, (ii) alkylidene malononitrile and stilbene conjugation events in the product, and (iii) an unexpected intramolecular π-π* stack on the product side of the equilibrium. The key substrates are rapidly assembled from simple starting materials, resulting in many successful examples. The products are structurally complex and bear vicinal stereocenters generated by the dearomative Cope rearrangement. They also contain a variety of functional groups for interconversion to complex architectures.
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Affiliation(s)
- Subhadip De
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32603, United States
| | - Breanna M Tomiczek
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32603, United States
| | - Yinuo Yang
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32603, United States
| | - Kenneth Ko
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32603, United States
| | - Ion Ghiviriga
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32603, United States
| | - Adrian Roitberg
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32603, United States
| | - Alexander J Grenning
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32603, United States
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3
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Sobie KM, Albritton M, Yang Y, Alves MM, Roitberg A, Grenning AJ. Construction of vicinal 4°/3°-carbons via reductive Cope rearrangement. Chem Sci 2022; 13:1951-1956. [PMID: 35308853 PMCID: PMC8848919 DOI: 10.1039/d1sc06307c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/20/2022] [Indexed: 11/21/2022] Open
Abstract
Herein reported is a strategy for constructing vicinal 4°/3° carbons via reductive Cope rearrangement. Substrates have been designed which exhibit Cope rearrangement kinetic barriers of ∼23 kcal mol−1 with isoenergetic favorability (ΔG ∼ 0). These fluxional/shape-shifting molecules can be driven forward by chemoselective reduction to useful polyfunctionalized building blocks. Herein reported is a strategy for constructing vicinal 4°/3° carbons via reductive Cope rearrangement.![]()
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Affiliation(s)
- Kristin M Sobie
- Department of Chemistry, University of Florida PO Box 117200 Gainesville FL 32611 USA
| | - Matthew Albritton
- Department of Chemistry, University of Florida PO Box 117200 Gainesville FL 32611 USA
| | - Yinuo Yang
- Department of Chemistry, University of Florida PO Box 117200 Gainesville FL 32611 USA
| | - Mariana M Alves
- Department of Chemistry, University of Florida PO Box 117200 Gainesville FL 32611 USA
| | - Adrian Roitberg
- Department of Chemistry, University of Florida PO Box 117200 Gainesville FL 32611 USA
| | - Alexander J Grenning
- Department of Chemistry, University of Florida PO Box 117200 Gainesville FL 32611 USA
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Mannchen MD, Ghiviriga I, Abboud KA, Grenning AJ. 1,2,4-Trifunctionalized Cyclohexane Synthesis via a Diastereoselective Reductive Cope Rearrangement and Functional Group Interconversion Strategy. Org Lett 2021; 23:8804-8809. [PMID: 34719933 DOI: 10.1021/acs.orglett.1c03310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Polyfunctionalized cyclohexanes are privileged scaffolds in drug discovery. Reported herein is a method for synthesizing 1,2,4-trifunctionalized cyclohexanes via diastereoselective reductive Cope rearrangement. The scaffolds obtained can be derivatized by orthogonal functional group interconversion to cyclohexanes bearing a 1-amide, 2-branched arylallyl, and variable 4-functional group.
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Affiliation(s)
- Michael D Mannchen
- Department of Chemistry, University of Florida, Gainesville, Florida 32603, United States
| | - Ion Ghiviriga
- Center for NMR Spectroscopy, Department of Chemistry, University of Florida, Gainesville, Florida 32603, United States
| | - Khalil A Abboud
- Center for X-ray Crystallography, Department of Chemistry, University of Florida, Gainesville, Florida 32603, United States
| | - Alexander J Grenning
- Department of Chemistry, University of Florida, Gainesville, Florida 32603, United States
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5
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Fereyduni E, Lahtigui O, Sanders JN, Tomiczek BM, Mannchen MD, Yu RA, Houk KN, Grenning AJ. Overcoming Kinetic and Thermodynamic Challenges of Classic Cope Rearrangements. J Org Chem 2021; 86:2632-2643. [PMID: 33476142 DOI: 10.1021/acs.joc.0c02690] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Systematic evaluation of 1,5-dienes bearing 3,3-electron-withdrawing groups and 4-methylation results in the discovery of a Cope rearrangement for Meldrum's acid-containing substrates that have unexpectedly favorable kinetic and thermodynamic profiles. The protocol is quite general due to a concise and convergent synthesis from abundant starting materials. Furthermore, products with an embedded Meldrum's acid moiety are prepared, which, in turn, can yield complex amides under neutral conditions. We have now expanded the scope of the reductive Cope rearrangement, which, via chemoselective reduction, can promote thermodynamically unfavorable [3,3] sigmatropic rearrangements of 3,3-dicyano-1,5-dienes to form reduced Cope rearrangement products. The Cope rearrangement is found to be stereospecific and can yield enantioenriched building blocks when chiral, nonracemic 1,3-disubstituted allylic electrophiles are utilized. We expand further the use of Cope rearrangements for the synthesis of highly valuable building blocks for complex- and drug-like molecular synthesis.
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Affiliation(s)
- Ehsan Fereyduni
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Ouidad Lahtigui
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Jacob N Sanders
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Breanna M Tomiczek
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Michael D Mannchen
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Roland A Yu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Alexander J Grenning
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
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Semenova E, Lahtigui O, Scott SK, Albritton M, Abboud KA, Ghiviriga I, Roitberg AE, Grenning AJ. Selective ring-rearrangement or ring-closing metathesis of bicyclo[3.2.1]octenes. Chem Commun (Camb) 2020; 56:11779-11782. [PMID: 32940291 DOI: 10.1039/d0cc04624h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Explored was the competitive ring-closing metathesis vs. ring-rearrangement metathesis of bicyclo[3.2.1]octenes prepared by a simple and convergent synthesis from bicyclic alkylidenemalono-nitriles and allylic electrophiles. It was uncovered that ring-closing metathesis occurs exclusively on the tetraene-variant, yielding unique, stereochemically and functionally rich polycyclic bridged frameworks, whereas the reduced version (a triene) undergoes ring-rearrangement metathesis to 5-6-5 fused ring systems resembling the isoryanodane core.
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Affiliation(s)
- Evgeniya Semenova
- Department of Chemistry, University of Florida, P. O. Box 117200, Gainesville, FL, USA.
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Diastereoselective Synthesis of 2,3,4-Trisubstituted Tetrahydrofurans via Thermally Reactive 1,5-Diene- tert-butyl Carbonates. Org Lett 2020; 22:842-847. [PMID: 31951142 DOI: 10.1021/acs.orglett.9b04306] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report that 3,3-dicyano-1,5-dienes bearing tert-butyl carbonates can be thermally converted to 2,3,4-trisubstituted tetrahydrofurans. The transformation relies on two thermally reactive functional groups, a 1,5-diene and a tert-butyl carbonate, that react cooperatively to yield the furan scaffolds by thermal Cope rearrangement, Boc deprotection, and oxy-Michael addition. Described herein is background related to the discovery, optimization, and scope of the key transformation and representative functional group interconversion chemistry for the tetrahydrofuran scaffolds.
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