1
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Trauner F, Ghazali R, Rettig J, Thiele CM, Didier D. Stereoselective polar radical crossover for the functionalization of strained-ring systems. Commun Chem 2024; 7:139. [PMID: 38898159 PMCID: PMC11187220 DOI: 10.1038/s42004-024-01221-3] [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: 01/18/2024] [Accepted: 06/06/2024] [Indexed: 06/21/2024] Open
Abstract
Radical-polar crossover of organoborates is a poweful tool that enables the creation of two C-C bonds simultaneously. Small ring systems have become essential motifs in drug discovery and medicinal chemistry. However, step-economic methods for their selective functionalization remains scarce. Here we present a one-pot strategy that merges a simple preparation of strained organoboron species with the recently popularized polar radical crossover of borate derivatives to stereoselectively access tri-substituted azetidines, cyclobutanes and five-membered carbo- and heterocycles.
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Affiliation(s)
- Florian Trauner
- Technische Universität Darmstadt, Clemens-Schöpf-Insitut für Organische Chemie und Biochemie, Peter-Grünberg-Str. 4, 64287, Darmstadt, Germany
- Ludwig-Maximilians Universität, Department Chemie, Butenandtstr. 5, 81377, München, Germany
| | - Rahma Ghazali
- Technische Universität Darmstadt, Clemens-Schöpf-Insitut für Organische Chemie und Biochemie, Peter-Grünberg-Str. 4, 64287, Darmstadt, Germany
| | - Jan Rettig
- Technische Universität Darmstadt, Clemens-Schöpf-Insitut für Organische Chemie und Biochemie, Peter-Grünberg-Str. 4, 64287, Darmstadt, Germany
| | - Christina M Thiele
- Technische Universität Darmstadt, Clemens-Schöpf-Insitut für Organische Chemie und Biochemie, Peter-Grünberg-Str. 4, 64287, Darmstadt, Germany
| | - Dorian Didier
- Technische Universität Darmstadt, Clemens-Schöpf-Insitut für Organische Chemie und Biochemie, Peter-Grünberg-Str. 4, 64287, Darmstadt, Germany.
- Ludwig-Maximilians Universität, Department Chemie, Butenandtstr. 5, 81377, München, Germany.
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2
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Dutta S, Lu YL, Erchinger JE, Shao H, Studer E, Schäfer F, Wang H, Rana D, Daniliuc CG, Houk KN, Glorius F. Double Strain-Release [2π+2σ]-Photocycloaddition. J Am Chem Soc 2024; 146:5232-5241. [PMID: 38350439 DOI: 10.1021/jacs.3c11563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
In pursuit of potent pharmaceutical candidates and to further improve their chemical traits, small ring systems can serve as a potential starting point. Small ring units have the additional merit of loaded strain at their core, making them suitable reactants as they can capitalize on this intrinsic driving force. With the introduction of cyclobutenone as a strained precursor to ketene, the photocycloaddition with another strained unit, bicyclo[1.1.0]butane (BCB), enables the reactivity of both π-units in the transient ketene. This double strain-release driven [2π+2σ]-photocycloaddition promotes the synthesis of diverse heterobicyclo[2.1.1]hexane units, a pharmaceutically relevant bioisostere. The effective reactivity under catalyst-free conditions with a high functional group tolerance defines its synthetic utility. Experimental mechanistic studies and density functional theory (DFT) calculations suggest that the [2π+2σ]-photocycloaddition takes place via a triplet mechanism.
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Affiliation(s)
- Subhabrata Dutta
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Yi-Lin Lu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Johannes E Erchinger
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Huiling Shao
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Emanuel Studer
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Felix Schäfer
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Huamin Wang
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Debanjan Rana
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Frank Glorius
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
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3
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Smyrnov V, Waser J. Semipinacol Rearrangement of Cyclopropenylcarbinols for the Synthesis of Highly Substituted Cyclopropanes. Org Lett 2023; 25:6999-7003. [PMID: 37707959 DOI: 10.1021/acs.orglett.3c02543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
An electrophile-induced semipinacol rearrangement of cyclopropenylcarbinols is reported. This transformation gives access to various polyfunctionalized cyclopropanes under mild metal-free conditions. The scope of the reaction includes iodine, sulfur and selenium electrophiles, aryl and strained ring migrating groups, and diverse substitution patterns on the cyclopropene. The reaction is particularly efficient for the synthesis of small ring-containing spirocycles, which are important rigid three-dimensional building blocks for medicinal chemistry.
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Affiliation(s)
- Vladyslav Smyrnov
- Laboratory of Catalysis and Organic Synthesis, Institut des Sciences et Ingénierie Chimique, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Jerome Waser
- Laboratory of Catalysis and Organic Synthesis, Institut des Sciences et Ingénierie Chimique, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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4
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Hsu CM, Lin HB, Hou XZ, Tapales RVPP, Shih CK, Miñoza S, Tsai YS, Tsai ZN, Chan CL, Liao HH. Azetidines with All-Carbon Quaternary Centers: Merging Relay Catalysis with Strain Release Functionalization. J Am Chem Soc 2023; 145:19049-19059. [PMID: 37589099 DOI: 10.1021/jacs.3c06710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Given the importance and beneficial characteristics of decorated azetidines in medicinal chemistry, efficient strategies for their synthesis are highly sought after. Herein, we report a facile synthesis of the elusive all-carbon quaternary-center-bearing azetidines. By adopting a well-orchestrated polar-radical relay strategy, ring strain release of bench-stable benzoylated 1-azabicyclo[1.1.0]butane (ABB) can be harnessed for nickel-catalyzed Suzuki Csp2-Csp3 cross-coupling with commercially available boronic acids in broad scope (>50 examples), excellent functional group tolerance, and gram-scale utility. Preliminary mechanistic studies provided insights into the underlying mechanism, wherein the ring opening of ABB with a catalytic quantity of bromide accounts for the conversion of ABB into a redox-active azetidine, which subsequently engages in the cross-coupling reaction through a radical pathway. The synergistic bromide and nickel catalysis could intriguingly be derived from a single nickel source (NiBr2). Application of the method to modify natural products, biologically relevant molecules, and pharmaceuticals has been successfully achieved as well as the synthesis of melanocortin-1 receptor (MC-1R) agonist and vesicular acetylcholine transporter (VAChT) inhibitor analogues through bioisosteric replacements of piperidine with azetidine moieties, highlighting the potential of the method in drug optimization studies. Aside from the synthesis of azetidines, we demonstrate the ancillary utility of our nickel catalytic system toward the restricted Suzuki cross-coupling of tertiary alkyl bromides with aryl boronic acids to construct all-carbon quaternary centers.
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Affiliation(s)
- Che-Ming Hsu
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Heng-Bo Lin
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Xin-Zhi Hou
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | | | - Chen-Kuei Shih
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Shinje Miñoza
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Yu-Syuan Tsai
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Zong-Nan Tsai
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Cheng-Lin Chan
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
| | - Hsuan-Hung Liao
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
- Green Hydrogen Research Center, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (R.O.C.)
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5
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Tyler JL, Aggarwal VK. Synthesis and Applications of Bicyclo[1.1.0]butyl and Azabicyclo[1.1.0]butyl Organometallics. Chemistry 2023; 29:e202300008. [PMID: 36786481 PMCID: PMC10947034 DOI: 10.1002/chem.202300008] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/11/2023] [Accepted: 02/14/2023] [Indexed: 02/15/2023]
Abstract
The use of metalated (aza)bicyclo[1.1.0]butanes in synthesis is currently experiencing a renaissance, as evidenced by the numerous reports in the last 5 years that have relied on such intermediates to undergo unique transformations or generate novel fragments. Since their discovery, these species have been demonstrated to participate in a wide range of reactions with carbon and heteroatom electrophiles, as well as metal complexes, to facilitate the rapid diversification of (aza)bicyclo[1.1.0]butane-containing compounds. Key to this is the relative acidity of the bridgehead C-H bonds which promotes facile deprotonation and subsequent functionalization of an unsubstituted position on the carbon framework via the intermediacy of a metalated (aza)bicyclo[1.1.0]butane. Additionally, the late-stage incorporation of deuterium atoms in strained fragments has led to the elucidation of numerous reaction mechanisms that involve strained bicycles. The continued investigation into the inimitable reactivity of metalated bicycles will cement their importance within the field of organometallic chemistry.
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Affiliation(s)
- Jasper L. Tyler
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
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6
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Jung M, Muir JE, Lindsay VNG. Expedient synthesis of spiro[3.3]heptan-1-ones via strain-relocating semipinacol rearrangements. Tetrahedron 2023; 134:133296. [PMID: 36937489 PMCID: PMC10019042 DOI: 10.1016/j.tet.2023.133296] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A novel approach for the formation of the highly strained spiro[3.3]heptan-1-one motif was developed through the reaction of 1-sulfonylcyclopropanols and lithiated 1-sulfonylbicyclo[1.1.0]butanes. Following initial nucleophilic addition to the cyclopropanone formed in situ, the resulting 1-bicyclobutylcyclopropanol intermediate is prone to a 'strain-relocating' semipinacol rearrangement in the presence of acid, directly affording the substituted spiro[3.3]heptan-1-one. The process is shown to be fully regio- and stereospecific when starting from a substituted cyclopropanone equivalent, leading to optically active 3-substituted spiro[3.3]heptan-1-ones. The reaction likely proceeds via initial protonation of the bicyclobutyl moiety followed by [1,2]-rearrangement of the resulting cyclopropylcarbinyl cation.
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Affiliation(s)
- Myunggi Jung
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695, United States
| | - Joanna E Muir
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695, United States
| | - Vincent N G Lindsay
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695, United States
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7
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Wölfl B, Winter N, Li J, Noble A, Aggarwal VK. Strain-Release Driven Epoxidation and Aziridination of Bicyclo[1.1.0]butanes via Palladium Catalyzed σ-Bond Nucleopalladation. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202217064. [PMID: 38516047 PMCID: PMC10952369 DOI: 10.1002/ange.202217064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Indexed: 12/14/2022]
Abstract
The development of preparative methods for the synthesis of four-membered carbocycles is gaining increasing importance due to the widespread utility of cyclic compounds in medicinal chemistry. Herein, we report the development of a new methodology for the production of spirocyclic epoxides and aziridines containing a cyclobutane motif. In a two-step one-pot process, a bicyclo[1.1.0]butyl sulfoxide is lithiated and added to a ketone, aldehyde or imine, and the resulting intermediate is cross-coupled with an aryl triflate through C-C σ-bond alkoxy- or aminopalladation with concomitant epoxide or aziridine formation. After careful optimization, a remarkably efficient reaction was conceived that tolerated a broad variety of both aromatic and aliphatic substrates. Lastly, through several high yielding ring-opening reactions, we demonstrated the excellent applicability of the products as modular building blocks for the introduction of three-dimensional structures into target molecules.
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Affiliation(s)
- Bernhard Wölfl
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Nils Winter
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Jiajing Li
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Adam Noble
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
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8
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Wölfl B, Winter N, Li J, Noble A, Aggarwal VK. Strain-Release Driven Epoxidation and Aziridination of Bicyclo[1.1.0]butanes via Palladium Catalyzed σ-Bond Nucleopalladation. Angew Chem Int Ed Engl 2023; 62:e202217064. [PMID: 36507714 PMCID: PMC10107310 DOI: 10.1002/anie.202217064] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022]
Abstract
The development of preparative methods for the synthesis of four-membered carbocycles is gaining increasing importance due to the widespread utility of cyclic compounds in medicinal chemistry. Herein, we report the development of a new methodology for the production of spirocyclic epoxides and aziridines containing a cyclobutane motif. In a two-step one-pot process, a bicyclo[1.1.0]butyl sulfoxide is lithiated and added to a ketone, aldehyde or imine, and the resulting intermediate is cross-coupled with an aryl triflate through C-C σ-bond alkoxy- or aminopalladation with concomitant epoxide or aziridine formation. After careful optimization, a remarkably efficient reaction was conceived that tolerated a broad variety of both aromatic and aliphatic substrates. Lastly, through several high yielding ring-opening reactions, we demonstrated the excellent applicability of the products as modular building blocks for the introduction of three-dimensional structures into target molecules.
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Affiliation(s)
- Bernhard Wölfl
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Nils Winter
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Jiajing Li
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Adam Noble
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
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9
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Abell J, Bold CP, Vicens L, Jentsch T, Velasco N, Tyler JL, Straker RN, Noble A, Aggarwal VK. Synthesis of Dihydropyridine Spirocycles by Semi-Pinacol-Driven Dearomatization of Pyridines. Org Lett 2023; 25:400-404. [PMID: 36626565 PMCID: PMC9872164 DOI: 10.1021/acs.orglett.2c04095] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The identification of the beneficial pharmacokinetic properties of aza-spirocycles has led to the routine incorporation of these highly rigid and three-dimensional structures in pharmaceuticals. Herein, we report an operationally simple synthesis of spirocyclic dihydropyridines via an electrophile-induced dearomative semi-pinacol rearrangement of 4-(1'-hydroxycyclobutyl)pyridines. The various points for diversification of the spirocyclization precursors, as well as the synthetic utility of the amine and ketone functionalities in the products, provide the potential to rapidly assemble medicinally relevant spirocycles.
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Affiliation(s)
- Joseph
C. Abell
- School
of Chemistry, University of Bristol, Cantock’s Close, BristolBS8 1TS, U.K.
| | - Christian P. Bold
- School
of Chemistry, University of Bristol, Cantock’s Close, BristolBS8 1TS, U.K.
| | - Laia Vicens
- School
of Chemistry, University of Bristol, Cantock’s Close, BristolBS8 1TS, U.K.
| | - Tom Jentsch
- School
of Chemistry, University of Bristol, Cantock’s Close, BristolBS8 1TS, U.K.
| | - Noelia Velasco
- School
of Chemistry, University of Bristol, Cantock’s Close, BristolBS8 1TS, U.K.
| | - Jasper L. Tyler
- School
of Chemistry, University of Bristol, Cantock’s Close, BristolBS8 1TS, U.K.
| | | | - Adam Noble
- School
of Chemistry, University of Bristol, Cantock’s Close, BristolBS8 1TS, U.K.
| | - Varinder K. Aggarwal
- School
of Chemistry, University of Bristol, Cantock’s Close, BristolBS8 1TS, U.K.,
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10
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Tyler JL, Noble A, Aggarwal VK. Four-Component Strain-Release-Driven Synthesis of Functionalized Azetidines. Angew Chem Int Ed Engl 2022; 61:e202214049. [PMID: 36300572 PMCID: PMC10099845 DOI: 10.1002/anie.202214049] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Indexed: 11/06/2022]
Abstract
Despite the favorable properties that azetidine rings can engender on drug-compounds, methods for the diversity-oriented synthesis of azetidine-based structures are significantly underdeveloped. Herein, we report the successful realization of a multicomponent [1,2]-Brook rearrangement/strain-release-driven anion relay sequence and its application to the modular synthesis of substituted azetidines. The rapidity of the reaction, as confirmed by in situ infra-red spectroscopy, leverages the strain-release ring-opening of azabicyclo[1.1.0]butane to drive the equilibrium of the Brook rearrangement. The three electrophilic coupling partners, added sequentially to azabicyclo[1.1.0]butyl-lithium, could be individually varied to access a diverse compound library. The utility of this methodology was demonstrated in a 4-step synthesis of the EP2 receptor antagonist PF-04418948.
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Affiliation(s)
- Jasper L Tyler
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Adam Noble
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Varinder K Aggarwal
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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11
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Musci P, Colella M, Andresini M, Aramini A, Degennaro L, Luisi R. Flow technology enabled preparation of C3-heterosubstituted 1-azabicyclo[1.1.0]butanes and azetidines: accessing unexplored chemical space in strained heterocyclic chemistry. Chem Commun (Camb) 2022; 58:6356-6359. [PMID: 35536561 DOI: 10.1039/d2cc01641a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of flow technology as an enabling tool for accessing 1-azabicyclo[1.1.0]butanes bearing strained 3-, 4-, and 5-membered O-heterocycles with C3(N-het)-C2(O-het) connectivity is reported. Reactivity and chemoselectivity (N-ring vs. O-ring) were also evaluated. New chemical space has been explored and new structural motifs such as ABB-aziridines or spiro azetidine-oxazetidines are also reported.
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Affiliation(s)
- Pantaleo Musci
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" Via E. Orabona 4, 70125, Bari, Italy.
| | - Marco Colella
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" Via E. Orabona 4, 70125, Bari, Italy.
| | - Michael Andresini
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" Via E. Orabona 4, 70125, Bari, Italy.
| | - Andrea Aramini
- Department of Discovery, Dompé Farmaceutici S.p.A., Via Campo di Pile, L'Aquila, 67100, Italy
| | - Leonardo Degennaro
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" Via E. Orabona 4, 70125, Bari, Italy.
| | - Renzo Luisi
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro" Via E. Orabona 4, 70125, Bari, Italy.
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12
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Tyler JL, Noble A, Aggarwal VK. Strain‐Release‐Driven Friedel–Crafts Spirocyclization of Azabicyclo[1.1.0]butanes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202114235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jasper L. Tyler
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Adam Noble
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
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13
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Tyler JL, Noble A, Aggarwal VK. Strain-Release-Driven Friedel-Crafts Spirocyclization of Azabicyclo[1.1.0]butanes. Angew Chem Int Ed Engl 2022; 61:e202114235. [PMID: 34780681 PMCID: PMC9299780 DOI: 10.1002/anie.202114235] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Indexed: 02/06/2023]
Abstract
The identification of spiro N-heterocycles as scaffolds that display structural novelty, three-dimensionality, beneficial physicochemical properties, and enable the controlled spatial disposition of substituents has led to a surge of interest in utilizing these compounds in drug discovery programs. Herein, we report the strain-release-driven Friedel-Crafts spirocyclization of azabicyclo[1.1.0]butane-tethered (hetero)aryls for the synthesis of a unique library of azetidine spiro-tetralins. The reaction was discovered to proceed through an unexpected interrupted Friedel-Crafts mechanism, generating a highly complex azabicyclo[2.1.1]hexane scaffold. This dearomatized intermediate, formed exclusively as a single diastereomer, can be subsequently converted to the Friedel-Crafts product upon electrophilic activation of the tertiary amine, or trapped as a Diels-Alder adduct in one-pot. The rapid assembly of molecular complexity demonstrated in these reactions highlights the potential of the strain-release-driven spirocyclization strategy to be utilized in the synthesis of medicinally relevant scaffolds.
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Affiliation(s)
- Jasper L. Tyler
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Adam Noble
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
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14
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Rao MLN, Islam SS. Rearrangement-Driven Molecular Diversity: Synthesis of Functionalized Pyrones, Orthoesters, and Xanthones from Spiroketals. Org Lett 2021; 23:8668-8672. [PMID: 34714091 DOI: 10.1021/acs.orglett.1c02888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of tricyclic 5,5-benzannulated spiroketals with trifluoroacetic acid (TFA) and AlCl3 furnished benzopyranobenzopyrans, benzofuro-orthoesters, and benzofuroxanthones. Whereas the reaction of tricyclic 5,5-benzannulated spiroketals with TFA produced the pyrones, the reaction with AlCl3 furnished densely functionalized orthoesters and xanthones. The formation of these products was rationalized by fascinating mechanistic pathways involving semipinacol/α-ketol molecular rearrangements.
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Affiliation(s)
- Maddali L N Rao
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Sk Shamim Islam
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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15
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Colella M, Musci P, Cannillo D, Spennacchio M, Aramini A, Degennaro L, Luisi R. Development of a Continuous Flow Synthesis of 2-Substituted Azetines and 3-Substituted Azetidines by Using a Common Synthetic Precursor. J Org Chem 2021; 86:13943-13954. [PMID: 34291947 DOI: 10.1021/acs.joc.1c01297] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The generation and functionalization, under continuous flow conditions, of two different lithiated four-membered aza-heterocycles is reported. N-Boc-3-iodoazetidine acts as a common synthetic platform for the genesis of C3-lithiated azetidine and C2-lithiated azetine depending on the lithiation agent. Flow technology enables easy handling of such lithiated intermediates at much higher temperatures compared to batch processing. Flow technology combined with cyclopentylmethyl ether as an environmentally responsible solvent allows us to address sustainability concerns.
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Affiliation(s)
- Marco Colella
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro", Via E. Orabona 4, 70125 Bari, Italy
| | - Pantaleo Musci
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro", Via E. Orabona 4, 70125 Bari, Italy
| | - Debora Cannillo
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro", Via E. Orabona 4, 70125 Bari, Italy
| | - Mauro Spennacchio
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro", Via E. Orabona 4, 70125 Bari, Italy
| | - Andrea Aramini
- Department of Discovery, Dompé Farmaceutici S.p.A., Via Campo di Pile, L'Aquila 67100, Italy
| | - Leonardo Degennaro
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro", Via E. Orabona 4, 70125 Bari, Italy
| | - Renzo Luisi
- FLAME-Lab, Flow Chemistry and Microreactor Technology Laboratory, Department of Pharmacy - Drug Sciences, University of Bari "A. Moro", Via E. Orabona 4, 70125 Bari, Italy
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16
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Pinkert T, Das M, Schrader ML, Glorius F. Use of Strain-Release for the Diastereoselective Construction of Quaternary Carbon Centers. J Am Chem Soc 2021; 143:7648-7654. [PMID: 33974436 DOI: 10.1021/jacs.1c03492] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Herein, we describe the formation of quaternary carbon centers with excellent diastereoselectivity via a strain-release protocol. An organometallic species is generated by Cp*Rh(III)-catalyzed C-H activation, which is then coupled with strained bicyclobutanes (BCBs) and a prochiral carbon electrophile in a three-component reaction. This work illustrates a rare example of BCBs in transition metal catalysis and demonstrates their broad potential to access novel reaction pathways. The method developed exhibits ample functional group tolerance, and the products can be further transformed into valuable α-quaternary β-lactones. Preliminary mechanistic investigations suggest a twofold C-C bond cleavage sequence involving σ-bond insertion and an ensuing β-carbon elimination event.
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Affiliation(s)
- Tobias Pinkert
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Mowpriya Das
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Malte L Schrader
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Frank Glorius
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany
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17
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Wierzba AJ, Gryko DT, Gryko D. Acylation of electrophilic bicyclo[1.1.0]butanes via Co/Ni-catalyzed reductive cross-coupling. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s1088424621500528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cyclobutane scaffold is appreciated in medicinal chemistry for its strained, well-defined three-dimensional structure. Consequently, methods for the synthesis of cyclobutyl derivatives have become highly desired, particularly those offering access to compounds with new patterns of substituents. Herein, an acylation of electrophilic strained molecules at the bridgehead carbon with [Formula: see text]-acyl-glutarimides is reported. For this, the polarity-reversal strategy based on cobalt catalysis that enables the generation of cyclobutyl radicals in a strain release event was harnessed. These nucleophilic species, in the presence of a Ni-complex, couple with [Formula: see text]-acyl-glutarimides to give cyclobutyl ketones in decent yields.
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Affiliation(s)
- Aleksandra J. Wierzba
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Daniel T. Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Dorota Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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18
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Tyler JL, Noble A, Aggarwal VK. Strain-Release Driven Spirocyclization of Azabicyclo[1.1.0]butyl Ketones. Angew Chem Int Ed Engl 2021; 60:11824-11829. [PMID: 33754432 PMCID: PMC8251566 DOI: 10.1002/anie.202102754] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Indexed: 12/16/2022]
Abstract
Due to their intrinsic rigidity, three-dimensionality and structural novelty, spirocyclic molecules have become increasingly sought-after moieties in drug discovery. Herein, we report a strain-release driven synthesis of azetidine-containing spirocycles by harnessing the inherent ring strain of the azabicyclo[1.1.0]butane (ABB) fragment. Novel ABB-ketone precursors bearing silyl-protected alcohols were synthesized in a single step and shown to engage in electrophile-induced spirocyclization-desilylation reactions. Primary, secondary and tertiary silyl ethers were effectively transformed into a library of new spiro-azetidines, with a range of substituents and ring sizes. In addition, the products are generated with synthetically useful ketone and protected-amine functional groups, which provides the potential for further elaboration and for this chemistry to be utilized in the rapid assembly of medicinally relevant compounds.
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Affiliation(s)
- Jasper L. Tyler
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Adam Noble
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
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19
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Kerner MJ, Wipf P. Semipinacol-Type Rearrangements of [3-(Arylsulfonyl)bicyclo[1.1.0]butan-1-yl]alkanols. Org Lett 2021; 23:3615-3619. [PMID: 33872016 DOI: 10.1021/acs.orglett.1c01004] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Selective lithiation of arylsulfonylbicyclo[1.1.0]butanes at the bridgehead methine and addition to carbonyl compounds yield tertiary bicyclobutyl alcohols that form spiro[3.4]octanes and related heteroatom-containing spirocycles via an acid- or halogen-mediated semipinacol rearrangement. Further synthetic transformations at the carbonyl or arylsulfone positions, in general in high yield and good chemoselectivity, allow access to acetals, difluorides, amides, and methylenecyclobutene building blocks.
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Affiliation(s)
- Michael J Kerner
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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20
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Tyler JL, Noble A, Aggarwal VK. Strain‐Release Driven Spirocyclization of Azabicyclo[1.1.0]butyl Ketones. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102754] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Jasper L. Tyler
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Adam Noble
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
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21
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Gregson CHU, Noble A, Aggarwal VK. Divergent, Strain-Release Reactions of Azabicyclo[1.1.0]butyl Carbinols: Semipinacol or Spiroepoxy Azetidine Formation. Angew Chem Int Ed Engl 2021; 60:7360-7365. [PMID: 33555105 PMCID: PMC8247891 DOI: 10.1002/anie.202100583] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Indexed: 12/17/2022]
Abstract
The azetidine moiety is a privileged motif in medicinal chemistry and new methods that access them efficiently are highly sought after. Towards this goal, we have found that azabicyclo[1.1.0]butyl carbinols, readily obtained from the highly strained azabicyclo[1.1.0]butane (ABB), can undergo divergent strain-release reactions upon N-activation. Treatment with trifluoroacetic anhydride or triflic anhydride triggered a semipinacol rearrangement to give keto 1,3,3-substituted azetidines. More than 20 examples were explored, enabling us to evaluate selectivity and the migratory aptitude of different groups. Alternatively, treatment of the same alcohols with benzyl chloroformate in the presence of NaI led to iodohydrin intermediates which gave spiroepoxy azetidines upon treatment with base. The electronic nature of the activating agent dictates which pathway operates.
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Affiliation(s)
| | - Adam Noble
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
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