Photocatalytic and catalytic activity of heterogenized W10O324− in the bromide-assisted bromination of arenes and alkenes in the presence of oxygen

Molinari, Alessandra; Varani, G.; Polo, Eleonora; Vaccari, Silvia; Maldotti, Andrea

doi:10.1016/j.molcata.2006.08.056

Cited by 49 publications

(21 citation statements)

References 35 publications

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“…[189] 2-Iodonaphthalene was predominantly formed from the reaction of naphthalene with iodine and oxygen over basic faujasite zeolites KX at 250 8C. The ratio of 2-iodonaphthalene to 1-iodonaphthalene can be reduced by substituting sodium for potassium in the zeolite, altering the faujasite zeolite Si/Al ratio, or increasing the amount of iodine.…”

Section: Nitrogen Compounds As Catalysts For Aerobic Oxidative Halogementioning

confidence: 99%

Oxidative Halogenation with “Green” Oxidants: Oxygen and Hydrogen Peroxide

2009

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It is difficult to imagine organic chemistry without organo-halogen compounds and the molecular halogens needed for their preparation. The halogens have very different reactivity, with iodine usually requiring some form of activation, while others are reactive and hazardous chemicals. To avoid their use, various modified reagents have been discovered (N-bromo- and N-chlorosuccinimide, Selectfluor..), but halogens are used to prepare these reagents and when they are used the atom economy is poor. A better approach, which is based on biomimetric research on oxidative halogenation in nature, consists of generating the halogenating reagent in situ under acidic conditions from a halide salt. The result of such a reaction has been halogenation with 100 % halogen atom economy. Suitable oxidants for the oxidation of halides are hydrogen peroxide and oxygen.

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Section: Nitrogen Compounds As Catalysts For Aerobic Oxidative Halogementioning

confidence: 99%

Oxidative Halogenation with “Green” Oxidants: Oxygen and Hydrogen Peroxide

2009

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“…Not only homogeneous photocatalysts such as Ir and Ru complexes but also heterogenous catalysts were introduced for bromination with visible light . Maldotti demonstrated that by introducing decatungstate with Amberlite IRA‐900 as a heterogeneous catalytic system, the bromination of alkenes could be achieved.…”

Section: Functionalizations Of Multiple Bonds With Halogensmentioning

confidence: 99%

Visible Light-Mediated Installation of Halogen Functionalities into Multiple Bond Systems

Kim

Kim²

2017

ChemistrySelect

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Photoredox catalysis has emerged as a useful tool for organic, synthetic, and material chemists to approach target molecules with new functionalities and structural complexity. This review focuses on the recent advances in the visible light‐promoted halogenation and trifluoromethylation/difluoromethylation of multiple bonds. Halogen functionalities are important chemical handles and building blocks in organic synthesis. Both electrophilic addition of halogens and radical halogenations are widely utilized in organic synthesis to install halogen functionalities. However, harsh conditions and low regioselectivity could present challenges. Despite these concerns, recent efforts have led to obvious advances in the visible light‐promoted halogenation of multiple bonds. In this context, we address the recent achievements in the visible light‐mediated installation of different types of halogen‐containing functionalities, which include (i) halogenation of unsaturated carbon‐carbon bonds, (ii) trifluoromethylation and difluoromethylation of π‐systems, and (iii) photoredox cyclization by insertion of fluorine sources. A variety of active catalytic species in the photoredox halogenations are also discussed in terms of their unique reactivity for the future development of highly practical and efficient processes.

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“…Photocatalyzed reactions were used to obtain dihydropyrazine by cyclization of propylene glycol with ethylenediamine [126], carbamate by carbonylation of p-nitrotoluene with EtOH [127], the monooxygenation and/or chlorination of cycloalkenes [75], monobrominated derivates from phenol and anisole [128], the addition of tertiary amines to alkenes [129], unsaturated amines adding cyclopentene and cyclohexene to imines [130], heterocyclic aldehydes by the reaction between heterocyclic bases and ethers [131], and propan-1-thiol by addition of H 2 S on propene. Photocatalyzed reactions were used to obtain dihydropyrazine by cyclization of propylene glycol with ethylenediamine [126], carbamate by carbonylation of p-nitrotoluene with EtOH [127], the monooxygenation and/or chlorination of cycloalkenes [75], monobrominated derivates from phenol and anisole [128], the addition of tertiary amines to alkenes [129], unsaturated amines adding cyclopentene and cyclohexene to imines [130], heterocyclic aldehydes by the reaction between heterocyclic bases and ethers [131], and propan-1-thiol by addition of H 2 S on propene.…”

Section: Functionalizationmentioning

confidence: 99%