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Zhou M, Mathew S, de Bruin B. Thermal and (Thermo-Reversible) Photochemical Cycloisomerization of 1 H-2-Benzo[ c]oxocins: From Synthetic Applications to the Development of a New T-Type Molecular Photoswitch. J Am Chem Soc 2022; 145:645-657. [PMID: 36548378 PMCID: PMC9837851 DOI: 10.1021/jacs.2c11310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A novel T-type molecular photoswitch based on the reversible cyclization of 1H-2-benzo[c]oxocins to dihydro-4H-cyclobuta[c]isochromenes has been developed. The switching mechanism involves a light-triggered ring-contraction of 8-membered 1H-2-benzo[c]oxocins to 4,6-fused O-heterocyclic dihydro-4H-cyclobuta[c]isochromene ring systems, with reversion back to the 1H-2-benzo[c]oxocin state accessible through heating. Both processes are unidirectional and proceed with good efficiency, with switching properties─including reversibility and half-life time─easily adjusted via structural functionalization. Our new molecular-switching platform exhibits independence from solvent polarity, originating from its neutral-charge switching mechanism, a property highly sought-after for biological applications. The photoinduced ring-contraction involves a [2+2] conjugated-diene cyclization that obeys the Woodward-Hoffmann rules. In contrast, the reverse process initiates via a thermal ring-opening (T > 60 °C) to produce the original 8-membered 1H-2-benzo[c]oxocins, which is thermally forbidden according to the Woodward-Hoffmann rules. The thermal ring-opening is likely to proceed via an ortho-quinodimethane (o-QDM) intermediate, and the corresponding switching mechanisms are supported by experimental observations and density functional theory calculations. Other transformations of 1H-2-benzo[c]oxocins were found upon altering reaction conditions: prolonged heating of the 1H-2-benzo[c]oxocins at a significantly elevated temperature (72 h at 120 °C), with the resulting dihydronaphthalenes formed via the o-QDM intermediate. These reactions also proceed with good chemoselectivities, providing new synthetic protocols for motifs found in several bioactive molecules, but are otherwise difficult to access.
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Pramanik A, Ghatak A, Khanra S, Das D, Rakshit T, Bhar S. Metal Free Approach towards the Synthesis of Structurally Diverse 1, 2‐Dihydronaphthalene Scaffolds and Theoretical Investigation. ChemistrySelect 2022. [DOI: 10.1002/slct.202201159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Amit Pramanik
- Department of Chemistry A. B. N. Seal College Cooch Behar Pin-736 101 West Bengal India
| | - Avishek Ghatak
- Department of Chemistry Dr. A. P. J. Abdul Kalam Government College Kolkata 700156 India
| | - Somnath Khanra
- Department of Chemistry A. B. N. Seal College Cooch Behar Pin-736 101 West Bengal India
- Department of Chemistry The University of Burdwan Bardhaman 713104 West Bengal India
| | - Debasis Das
- Department of Chemistry The University of Burdwan Bardhaman 713104 West Bengal India
| | - Tatini Rakshit
- Department of Chemistry School of Natural Sciences Shiv Nadar University Dadri UP 201314 India
| | - Sanjay Bhar
- Department of Chemistry Organic Chemistry Section Jadavpur University Kolkata 700 032 India
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Zhou M, Wolzak LA, Li Z, de Zwart FJ, Mathew S, de Bruin B. Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers. J Am Chem Soc 2021; 143:20501-20512. [PMID: 34802239 PMCID: PMC8662738 DOI: 10.1021/jacs.1c10927] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Indexed: 12/30/2022]
Abstract
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
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Affiliation(s)
- Minghui Zhou
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Lukas A. Wolzak
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Zirui Li
- Department
of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333
CC Leiden, The Netherlands
| | - Felix J. de Zwart
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Simon Mathew
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous,
Supramolecular and Bio-Inspired Catalysis (HomKat) group, Van ‘t
Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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Karki BS, Pramanik MMD, Kant R, Rastogi N. Visible light catalyzed reaction of α-bromochalcones with chalcones: direct access to the urundeuvine scaffold. Org Biomol Chem 2018; 16:7152-7156. [DOI: 10.1039/c8ob01881b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The α-keto vinyl radicals generated from α-bromochalcones under visible light photoredox catalyzed conditions were trapped by chalcones.
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Affiliation(s)
- Bhupal Singh Karki
- Medicinal and Process Chemistry Division
- CSIR-Central Drug Research Institute
- Lucknow 226031
- India
- Academy of Scientific and Innovative Research
| | - Mukund M. D. Pramanik
- Medicinal and Process Chemistry Division
- CSIR-Central Drug Research Institute
- Lucknow 226031
- India
- Academy of Scientific and Innovative Research
| | - Ruchir Kant
- Molecular & Structural Biology Division
- CSIR-Central Drug Research Institute
- Lucknow 226031
- India
| | - Namrata Rastogi
- Medicinal and Process Chemistry Division
- CSIR-Central Drug Research Institute
- Lucknow 226031
- India
- Academy of Scientific and Innovative Research
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Te Grotenhuis C, Das BG, Kuijpers PF, Hageman W, Trouwborst M, de Bruin B. Catalytic 1,2-dihydronaphthalene and E-aryl-diene synthesis via Co III-Carbene radical and o-quinodimethane intermediates. Chem Sci 2017; 8:8221-8230. [PMID: 29568470 PMCID: PMC5857932 DOI: 10.1039/c7sc03909c] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/11/2017] [Indexed: 11/21/2022] Open
Abstract
Catalytic synthesis of substituted 1,2-dihydronaphthalenes via metalloradical activation of o-styryl N-tosyl hydrazones ((E)-2-(prop-1-en-1-yl)benzene-N-tosyl hydrazones) is presented, taking advantage of the intrinsic reactivity of a cobalt(iii)-carbene radical intermediate. The method has been successfully applied to a broad range of substrates with various R1 substituents at the aromatic ring, producing the desired ring products in good to excellent isolated yields for substrates with an R2 = COOEt substituent at the vinylic position (∼70-90%). Changing the R2 moiety from an ester to other substituents has a surprisingly large influence on the (isolated) yields. This behaviour is unexpected for a radical rebound ring-closure mechanism, and points to a mechanism proceeding via ortho-quinodimethane (o-QDM) intermediates. Furthermore, substrates with an alkyl substituent on the allylic position reacted to form E-aryl-dienes in excellent yields, rather than the expected 1,2-dihydronaphthalenes. This result, combined with the outcome of supporting DFT calculations, strongly points to the release of reactive o-QDM intermediates from the metal centre in all cases, which either undergo a 6π-cyclisation step to form the 1,2-dihydronaphthalenes, or a [1,7]-hydride shift to produce the E-aryl-dienes. Trapping experiments using TEMPO confirm the involvement of cobalt(iii)-carbene radical intermediates. EPR spectroscopic spin-trapping experiments using phenyl N-tert-butylnitrone (PBN) confirm the radical nature of the catalytic reaction.
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Affiliation(s)
- Colet Te Grotenhuis
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) Group , Van 't Hoff Institute for Molecular Sciences (HIMS) , University of Amsterdam , Science Park 904 , 1098 XH Amsterdam , The Netherlands .
| | - Braja G Das
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) Group , Van 't Hoff Institute for Molecular Sciences (HIMS) , University of Amsterdam , Science Park 904 , 1098 XH Amsterdam , The Netherlands .
| | - Petrus F Kuijpers
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) Group , Van 't Hoff Institute for Molecular Sciences (HIMS) , University of Amsterdam , Science Park 904 , 1098 XH Amsterdam , The Netherlands .
| | - Wouter Hageman
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) Group , Van 't Hoff Institute for Molecular Sciences (HIMS) , University of Amsterdam , Science Park 904 , 1098 XH Amsterdam , The Netherlands .
| | - Mees Trouwborst
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) Group , Van 't Hoff Institute for Molecular Sciences (HIMS) , University of Amsterdam , Science Park 904 , 1098 XH Amsterdam , The Netherlands .
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis (HomKat) Group , Van 't Hoff Institute for Molecular Sciences (HIMS) , University of Amsterdam , Science Park 904 , 1098 XH Amsterdam , The Netherlands .
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Zanotti-Gerosa A, Gazić Smilović I, Časar Z. Acid promoted Ir–P^N complex catalyzed hydrogenation of heavily hindered 3,4-diphenyl-1,2-dihydronaphthalenes: asymmetric synthesis of lasofoxifene tartrate. Org Chem Front 2017. [DOI: 10.1039/c7qo00525c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
An asymmetric hydrogenation of minimally functionalized tetrasubstituted cyclic olefins has been developed using an Ir–P^N catalyst and an acid additive enabling the synthesis of lasofoxifene tartrate.
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Affiliation(s)
| | - Ivana Gazić Smilović
- Lek Pharmaceuticals
- d.d
- Sandoz Development Center Slovenia
- SI-1526 Ljubljana
- Slovenia
| | - Zdenko Časar
- Lek Pharmaceuticals
- d.d
- Sandoz Development Center Slovenia
- SI-1526 Ljubljana
- Slovenia
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Dharuman S, Palanivel AK, Vankar YD. An easy route to synthetic analogues of radicamine B, codonopsine and codonopsinine from d-mannitol. Org Biomol Chem 2014; 12:4983-98. [DOI: 10.1039/c4ob00503a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Yoshida H, Yoshida R, Mukae M, Ohshita J, Takaki K. Anortho-Quinodimethane Route to Lasofoxifene and U23469. CHEM LETT 2011. [DOI: 10.1246/cl.2011.1272] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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