Vår forskning är fokuserad på:
- Utveckling av effektiva syntesmetoder för hypervalenta jodreagens
- Utveckling av metallfria tillämpningsområden för hypervalenta jodreagens
- Mekanokemi

Några av våra mest citerade publikationer:

Eleanor A. Merritt and Berit Olofsson*
Diaryliodonium salts – from Obscurity to Fame
Angew. Chem. Int. Ed. 2009, 48, 9052-9070. Link  (>860 citations)

Marcin Bielawski, Mingzhao Zhu and Berit Olofsson*
Efficient and General One-Pot Synthesis of Diaryliodonium Triflates: Scope and Limitations
Adv. Synth. Catal. 2007, 349, 2610-2618. Link  (>330 citations)

Frithjof C. Küpper,* Martin C. Feiters, Berit Olofsson, Tatsuo Kaiho, Shozo Yanagida, Michael B. Zimmermann, Lucy J. Carpenter, George W. Luther III, Zunli Lu, Mats Jonsson and Lars Kloo    
Commemorating two centuries of iodine research: An interdisciplinary overview of current research
Angew. Chem. Int. Ed.  2011, 50, 11598-11620. Link  (>270 citations)

Marcin Bielawski, David Aili and Berit Olofsson*
Regiospecific One-Pot Synthesis of Diaryliodonium Tetrafluoroborates from Arylboronic Acids and Aryl Iodides
J. Org. Chem. 2008, 73, 4602-4607. Link   (>240 citations)

Joel Malmgren, Stefano Santoro, Nazli Jalalian, Fahmi Himo* and Berit Olofsson* Arylation with Unsymmetrical Diaryliodonium Salts – a Chemoselectivity Study 
Chem. Eur. J. 2013, 19, 10334-10342.  Link   (>200 citations)

Nazli Jalalian, Eloisa E. Ishikawa, Luiz F. Silva Jr. and Berit Olofsson*
Room Temperature, Metal-Free Synthesis of Diaryl Ethers with Use of Diaryliodonium Salts 
Org. Lett. 2011, 13, 1552-1555. Link     (>170 citations)

I urval från Stockholms universitets publikationsdatabas

• Synthesis of Complex Diarylamines through a Ring-Opening Difunctionalization Strategy

  2023. Erika Linde, Berit Olofsson. Angewandte Chemie International Edition 62 (48)

  Artikel

  The diarylation and skeletal diversification of unstrained cyclic amines was exploited to expand and modify the favorable properties of this important substrate class with pivotal roles in drug discovery. Cyclic amines were employed in the synthesis of a novel class of amino-substituted diaryliodonium salts, which were converted to highly functionalized diarylamines through an atom-efficient one-pot N-arylation/ring opening reaction with external nucleophiles. The reaction proceeds through in situ formation of a diarylammonium intermediate that undergoes a nucleophilic ring opening by cleavage of the strong C−N bond. A wide variety of diarylamines was obtained through introduction of two different aryl groups of varied electronics, and the retained iodo-substituent enables downfield diversifications of the products. More than 20 nucleophiles, including amines, phenols, carboxylic acids, thiols and halides, were alkylated with high functional group tolerance, and the strategy proved efficient also in in late-stage functionalization of natural products and pharmaceuticals. 

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• Stereospecific Photoredox-Catalyzed Vinylations to Functionalized Alkenes and C-Glycosides

  2023. Kumar Bhaskar Pal (et al.). Angewandte Chemie International Edition 62 (20)

  Artikel

  We report an efficient radical-mediated C-C coupling through photoredox-catalyzed reactions of 4-alkyl-dihydropyridines (DHPs) and vinylbenziodoxol(on)es (VBX, VBO). This transition-metal-free and mild photocatalytic method has excellent functional group tolerance and affords vinylated products in good yields, with complete retention of the alkene configuration. The utility of the methodology is demonstrated by the diastereoselective synthesis of C-vinyl glycosides. Preliminary mechanistic studies suggest that the C-C bond formation is stereospecific and proceeds through a concerted radical coupling transition state.

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• Explaining Regiodivergent Vinylations with Vinylbenziodoxolones

  2022. Ester Maria Di Tommaso, Per-Ola Norrby, Berit Olofsson. Angewandte Chemie International Edition 61 (34)

  Artikel

  Vinylbenziodoxolones have recently been identified as efficient hypervalent iodine(III) reagents for electrophilic vinylations under transition metal-free conditions. Their unique reactivity allows synthesis of either internal or terminal alkenes, depending on the nucleophile class. This paper constitutes the first mechanistic investigation of VBX vinylations, and makes use of NMR studies, deuterium labelling and computations to rationalize the observed regio- and stereochemical outcome. Internal alkene formation in S-vinylation was found to proceed through the ligand coupling mechanism typical of diaryliodonium salts, whereas terminal alkene formation in P-vinylations took place via a phosphinous acid-coordinated VBX complex, which underwent concerted deprotonation and Michael-type addition. Subsequent base-assisted protonation and E2 elimination delivered the terminal alkene. The findings can be used to predict the regioselectivity in vinylations of other nucleophile classes. 

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• Diarylation of N- and O-nucleophiles through a metal-free cascade reaction

  2022. Erika Linde (et al.). Chem 8 (3), 850-865

  Artikel

  The arylation of heteroatom nucleophiles is a central strategy to reach diarylated compounds that are key building blocks in agrochemicals, materials, and pharmaceuticals. Nucleophilic aromatic substitution is a classical tool for such arylations, and recent developments in hypervalent iodine-mediated arylations allow a wider scope of products. Herein, we combine the benefits of these strategies to enable an efficient and transition-metal-free difunctionalization of N-and O-nucleophiles with two structurally different aryl groups and to provide di-and triarylamines and diaryl ethers in one single step (>100 examples). The core of this strategy is the unique reactivity discovered with specifically designed fluorinated diaryliodonium salts, which unveils novel reaction pathways in hypervalent iodine chemistry. The methodology is suitable for diarylation of aliphatic amines, anilines, ammonia, and even water. It tolerates a wide variety of functional and protecting groups, with the retained iodine substituent easily accessible for derivatization of the products.

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• Electrophilic Vinylation of Thiols under Mild and Transition Metal-Free Conditions

  2020. Laura Castoldi (et al.). Angewandte Chemie International Edition 59 (36), 15512-15516

  Artikel

  The iodine(III) reagents vinylbenziodoxolones (VBX) were employed to vinylate a series of aliphatic and aromatic thiols, providing E-alkenyl sulfides with complete chemo- and regioselectivity, as well as excellent stereoselectivity. The methodology displays high functional group tolerance and proceeds under mild and transition metal-free conditions without the need for excess substrate or reagents. Mercaptothiazoles could be vinylated under modified conditions, resulting in opposite stereoselectivity compared to previous reactions with vinyliodonium salts. Novel VBX reagents with substituted benziodoxolone cores were prepared, and improved reactivity was discovered with a dimethyl-substituted core.

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• Regiospecific N-Arylation of Aliphatic Amines under Mild and Metal-Free Reaction Conditions

  2018. Nibadita Purkait (et al.). Angewandte Chemie International Edition 57 (35), 11427-11431

  Artikel

  A transition metal-free N-arylation of primary and secondary amines with diaryliodonium salts is presented. Both acyclic and cyclic amines are well tolerated, providing a large set of N-alkyl anilines. The methodology is unprecedented among metal-free methods in terms of amine scope, the ability to transfer both electron-withdrawing and electron-donating aryl groups, and efficient use of resources, as excess substrate or reagents are not required.

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• Transition metal-free, chemoselective arylation of thioamides yielding aryl thioimidates or N-aryl thioamides

  2018. Piret Villo, Gabriella Kervefors, Berit Olofsson. Chemical Communications 54 (64), 8810-8813

  Artikel

  Reactions of secondary thioamides with diaryliodonium salts under basic, transition metal-free conditions resulted in chemoselective S-arylation to provide aryl thioimidates in good to excellent yields. Equimolar amounts of thioamide, base and diaryliodonium salt were sufficient to obtain a diverse selection of products within short reaction times. Reactions with thiolactams delivered N-arylated thioamides in good yield at room temperature.

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• Competing Pathways in O-Arylations with Diaryliodonium Salts

  2017. Elin Stridfeldt (et al.). Chemistry - A European Journal 23 (53), 13249-13258

  Artikel

  A mechanistic study of arylations of aliphatic alcohols and hydroxide with diaryliodonium salts, to give alkyl aryl ethers and diaryl ethers, has been performed using experimental techniques and DFT calculations. Aryne intermediates have been trapped, and additives to avoid by-product formation originating from arynes have been found. An alcohol oxidation pathway was observed in parallel to arylation; this is suggested to proceed by an intramolecular mechanism. Product formation pathways via ligand coupling and arynes have been compared, and 4-coordinated transition states were found to be favored in reactions with alcohols. Furthermore, a novel, direct nucleophilic substitution pathway has been identified in reactions with electron-deficient diaryliodonium salts.

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• Efficient O-Functionalization of Carbohydrates with Electrophilic Reagents

  2016. Gergely L. Tolnai, Ulf J. Nilsson, Berit Olofsson. Angewandte Chemie International Edition 55 (37), 11226-11230

  Artikel

  Novel methodology for O-functionalization of carbohydrate derivatives has been established using bench-stable and easily prepared iodonium(III) reagents. Both electron-withdrawing and electron-donating aryl groups were introduced under ambient conditions and without precautions to exclude air or moisture. Furthermore, the approach was extended both to full arylation of cyclodextrin, and to trifluoroethylation of carbohydrate derivatives. This is the first general approach to introduce traditionally non-electrophilic groups into any of the OH groups around the sugar backbone. The methodology will be useful both in synthetic organic chemistry and biochemistry, as important functional groups can be incorporated under simple and robust reaction conditions in a fast and efficient manner.

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• One-Pot C-H Functionalization of Arenes by Diaryliodonium Salts

  2016. Marcus Reitti, Piret Villo, Berit Olofsson. Angewandte Chemie International Edition 55 (31), 8928-8932

  Artikel

  A transition-metal-free, mild, and highly regioselective synthesis of nitroarenes from arenes has been developed. The products are obtained in a sequential one-pot reaction by nitration of iodine(III) reagents with two carbon ligands, which are formed in situ from iodine(I). This novel concept has been extended to formation of aryl azides, and constitutes an important step towards catalytic reactions with these hypervalent iodine reagents. An efficient nitration of isolated diaryl-iodonium salts has also been developed, and the mechanism is proposed to proceed by a [2,2] ligand coupling pathway.

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• Arylation with Diaryliodonium Salts

  2016. Berit Olofsson. Hypervalent Iodine Chemistry, 135-166

  Kapitel

  This chapter focuses on recent developments in metal-free and metal-catalyzed arylations with diaryliodonium salts (diaryl-λ3-iodanes). Synthetic routes to diaryliodonium salts are briefly described, and chemoselectivity trends with unsymmetric iodonium salts are discussed.

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• Synthesis, Characterization and Unusual Reactivity of Vinylbenziodoxolones-Novel Hypervalent Iodine Reagents

  2016. Elin Stridfeldt (et al.). Chemistry - A European Journal 22 (45), 16066-16070

  Artikel

  A novel type of hypervalent iodine(III) reagents, vinylbenziodoxolones (VBX), has been synthesized in a one-pot reaction from 2-iodobenzoic acid. VBX is bench stable, has been thoroughly characterized and the cyclic structure is supported by X-ray analysis. The reactivity of VBX was investigated in vinylation of nitrocyclohexane, and delivered vinylated products with opposite regioselectivity compared to acyclic vinyl(aryl) iodonium salts. The reagents could become a powerful tool in vinylation reactions under both metal-free and metal-catalyzed conditions.

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• Room temperature, metal-free synthesis of diaryl ethers with use of diaryliodonium salts

  2011. Nazli Jalalian (et al.). Abstracts of Papers, 242nd ACS National Meeting & Exposition, Denver, CO, United States, August 28-September 1, 2011

  Konferens

  Diaryl ethers are common structural features in numerous natural products and biol. active compds.  Despite more than a century of immense focus on finding efficient synthetic routes to this compd. class, diaryl ethers remain difficult to obtain.  Routes that are catalytic in copper have been developed, but high catalyst loadings, excess reagents, elevated temps. and long reaction times are still needed.  Pd-catalyzed cross-couplings of phenols and aryl halides at temps. up to 100 °C have recently been reported to give high yields of diaryl ethers.  Diaryliodonium salts are non-toxic alternatives to transition metals in the synthesis of diaryl ethers and we have recently developed effective synthetic routes to these salts.  Herein we report a fast, high-yielding synthesis of diaryl ethers.  The reaction conditions are mild, metal-free, and avoid the use of halogenated solvents, additives, or excess reagents.  Precautions to avoid air or moisture are not needed.  The scope includes ortho- and halo-substituted diaryl ethers, which are difficult to obtain by metal-catalyzed protocols .

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• Diaryliodonium salts: A journey from obscurity to fame

  2009. Eleanor A. Merritt, Berit Olofsson. Angewandte Chemie International Edition 48 (48), 9052-9070

  Artikel

  The recent groundbreaking developments in the application of diaryliodonium salts in cross-coupling reactions has brought this class of previously underdeveloped reagents to the forefront of organic chemistry. With the advent of novel, facile, and efficient synthetic routes to these compounds, many more applications can be foreseen. Herein we provide an overview of the historical and recent advances in the synthesis and applications of diaryliodonium salts.

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• Regiospecific One-Pot Synthesis of Diaryliodonium Tetrafluoroborates from Arylboronic Acids and Aryl Iodides

  2008. Marcin Bielawski, David Aili, Berit Olofsson. Journal of Organic Chemistry 73 (12), 4602-4607

  Artikel

  Diaryliodonium salts have recently received considerable attention as mild arylation reagents in organic synthesis. This paper describes a regiospecific, sequential one-pot synthesis of symmetrical and unsymmetrical diaryliodonium tetrafluoroborates, which are the most popular salts in metal-catalyzed arylations. The protocol is fast and high-yielding and has a large substrate scope. Furthermore, the corresponding diaryliodonium triflates can conveniently be obtained via an in situ anion exchange.

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• Efficient and general one-pot synthesis of diaryliodonium triflates: scope and limitations

  2007. Marcin Bielawski, Mingzhao Zhu, Berit Olofsson. SIS Report, 19-22

  Konferens

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