Cobalt-Catalyzed Hydrofluorination of Unactivated Olefins: A Radical Approach of Fluorine Transfer

Shigehisa, Hiroki; Nishi, Eriko; Fujisawa, Mayu; Hiroya, Kou

doi:10.1021/ol402696h

Cited by 142 publications

(85 citation statements)

References 41 publications

(23 reference statements)

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“…Hydrofluorination is achieved with Nfluorotrimethylpyridinium tetrafluoroborate and (Me 2 SiH) 2 O under cobalt catalysis. [5,6] By using a substituted hepta-1,6-diene, cyclization occurred, and is consistent with the intermediacy of a 5-hexenyl radical (Scheme 1 b). Sadighi and co-workers [7] reported a unique trans hydrofluorination of internal alkynes catalyzed by electrophilic (NHC)gold(I) complexes, a reaction which was further developed by Miller and co-workers, [8] and it is regio-and stereoselective, but is not applicable to alkenes (Scheme 1 c).…”

supporting

confidence: 62%

“…[9] This important class of substrates is not amenable to hydrofluorination using known protocols. [4,5] The hydropalladation of styrenes is known to lead to h 3 -benzyl complexes responsive to benzylic functionalization, but not to fluorination. [10] Ultimately, our successful route uses an excess of Selectfluor, which acts both as an electrophilic fluorinating agent and an oxidant at different stages in the catalytic cycle (Scheme 1 d).…”

mentioning

confidence: 99%

“…[11,14] The method gave access to 2 u and 2 v, two compounds that possess three benzylic positions, and are not accessible by direct benzylic C À H activation/fluorination [9] or by applying the iron(III)-mediated or cobalt-catalyzed hydrofluorinations previously reported. [4,5] Pleasingly, (E)-and (Z)-2-benzylidene-3-methylbutan-1-ol (1 x) gave anti-2 x and syn-2 x, respectively, in good yields and with a d.r value of greater than 20:1. This result implies that the hydrofluorination is cis specific.…”

mentioning

confidence: 99%

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cis‐Specific Hydrofluorination of Alkenylarenes under Palladium Catalysis through an Ionic Pathway

et al. 2014

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This paper describes the hydrofluorination of alkenes through sequential H À and F + addition under palladium catalysis. The reaction is cis specific, thus providing access to benzylic fluorides. The mechanism of this reaction involves an ionic pathway and is distinct from known hydrofluorinations involving radical intermediates. The first catalytic enantioselective hydrofluorination is also disclosed.

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confidence: 62%

mentioning

confidence: 99%

mentioning

confidence: 99%

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cis‐Specific Hydrofluorination of Alkenylarenes under Palladium Catalysis through an Ionic Pathway

et al. 2014

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“…271 The catalytic cycle was presumably initiated by generation of Co-F complex 503 using an electrophilic fluorine source ( 23 ), which reacted with (Me 2 SiH) 2 O to form a cobalt hydride 450 . The driving force of this process was suggested as the strong Si-F bonding energy and was previously observed by Holland et al .…”

Section: Mechanistic Overviewmentioning

confidence: 99%

Mn-, Fe-, and Co-Catalyzed Radical Hydrofunctionalizations of Olefins

et al. 2016

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Cofactor-mimetic aerobic oxidation has conceptually merged with catalysis of syngas reactions to form a wide range of Markovnikov-selective olefin radical hydrofunctionalizations. We cover the development of the field and review contributions to reaction invention, mechanism and application to complex molecule synthesis. We also provide a mechanistic framework for understanding this compendium of radical reactions.

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“…515 In contrast to the aforementioned hydrochlorination reaction where PhSiH 3 was the optimal hydride source, 1,1,3,3-tetramethyldisiloxane was superior in the hydrofluorination process. 516 The proposed mechanism (Scheme 328) involves conversion of the Co(II) precatalyst to Co(III)F complex 535 via interaction with the pyridinium-based fluoride source.…”

Section: Co- Rh- and Ir-catalyzed Reactionsmentioning

confidence: 99%

Modern Transition-Metal-Catalyzed Carbon–Halogen Bond Formation

2016

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The high utility of halogenated organic compounds has prompted the development of a vast number of transformations which install the carbon-halogen motif. Traditional routes to these building blocks have commonly involved multiple steps, harsh reaction conditions, and the use of stoichiometric and/or toxic reagents. In this regard, using transition metals to catalyze the synthesis of organohalides has become a mature field in itself, and applying these technologies has allowed for a decrease in the production of waste, higher levels of regio- and stereoselectivity, and the ability to produce enantioenriched target compounds. Furthermore, transition metals offer the distinct advantage of possessing a diverse spectrum of mechanistic possibilities which translate to the capability to apply new substrate classes and afford novel and difficult-to-access structures. This Review provides comprehensive coverage of modern transition metal-catalyzed syntheses of organohalides via a diverse array of mechanisms. Attention is given to the seminal stoichiometric organometallic studies which led to the corresponding catalytic processes being realized. By breaking this field down into the synthesis of aryl, vinyl, and alkyl halides, it becomes clear which methods have surfaced as most favored for each individual class. In general, a pronounced shift toward the use of C-H bonds as key functional groups, in addition to methods which proceed by catalytic, radical-based mechanisms has occurred. Although always evolving, this field appears to be heading in the direction of using starting materials with a significantly lower degree of prefunctionalization in addition to less expensive and abundant metal catalysts.

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Cobalt-Catalyzed Hydrofluorination of Unactivated Olefins: A Radical Approach of Fluorine Transfer

Cited by 142 publications

References 41 publications

cis‐Specific Hydrofluorination of Alkenylarenes under Palladium Catalysis through an Ionic Pathway

cis‐Specific Hydrofluorination of Alkenylarenes under Palladium Catalysis through an Ionic Pathway

Mn-, Fe-, and Co-Catalyzed Radical Hydrofunctionalizations of Olefins

Modern Transition-Metal-Catalyzed Carbon–Halogen Bond Formation

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