A General Strategy Toward Aromatic 1,2‐Ambiphilic Synthons: Palladium‐Catalyzed <i>ortho</i>‐Halogenation of PyDipSi‐Arenes

Dudnik, Alexander S.; Chernyak, Natalia; Huang, Chunhui; Gevorgyan, Vladimir

doi:10.1002/ange.201004426

Cited by 44 publications

(14 citation statements)

References 51 publications

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“…[3] However, these reactions generally require the use of harsh reaction conditions: high temperature and/or acidic conditions. [4] More recently, the development of milder reaction conditions has become the subject of deep investigations. [5,6] To date, the most prominent examples of groups able to direct mild CÀH activation reactions can be divided in two main categories: amino and carbonyl-based derivatives.…”

Section: Introductionmentioning

confidence: 99%

Room‐Temperature ortho‐Alkoxylation and ‐Halogenation of N‐Tosylbenzamides by Using Palladium(II)‐Catalyzed CH Activation

Péron

Fossey

Santos

et al. 2014

Chemistry A European J

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The N-tosylcarboxamide group can direct the room-temperature palladium-catalyzed C-H alkoxylation and halogenation of substituted arenes in a simple and mild procedure. The room-temperature stoichiometric cyclopalladation of N-tosylbenzamide was first studied, and the ability of the palladacycle to react with oxidants to form C-X and C-O bonds under mild conditions was demonstrated. The reaction conditions were then adapted to promote room-temperature ortho-alkoxylations and ortho-halogenations of N-tosylbenzamides using palladium as catalyst. The scope and limitation of both alkoxylations and halogenations was studied and the subsequent functional transformation of the N-tosylcarboxamide group through nucleophilic additions was evaluated. This methodology offers a simple and mild route to diversely functionalized arenes.

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Section: Introductionmentioning

confidence: 99%

Room‐Temperature ortho‐Alkoxylation and ‐Halogenation of N‐Tosylbenzamides by Using Palladium(II)‐Catalyzed CH Activation

Péron

Fossey

Santos

et al. 2014

Chemistry A European J

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“…On the other hand, migratory cycloisomerization are important processes in contemporary catalysis [41]. In this context, our group is interested in C–H functionalization reactions of arenes involving propargylic derivatives [42].…”

Section: Introductionmentioning

confidence: 99%

Gold(I)-catalyzed hydroarylation reaction of aryl (3-iodoprop-2-yn-1-yl) ethers: synthesis of 3-iodo-2H-chromene derivatives

Morán-Poladura¹,

Rubio²,

González³

2013

Beilstein J. Org. Chem.

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SummaryAn efficient entry to the preparation of elusive 4-unsubstituted-3-iodo-2H-chromenes has been accomplished as result of a catalytic cyclization. Thus, upon exposition of [(3-iodoprop-2-yn-1-yl)oxy]arenes to IPrAuNTf2 (3 mol %), in 1,4-dioxane at 100 °C, the desired heterocyclic motif is readily assembled. This process nicely tolerates a variety of functional groups and, interestingly, it is compatible with the presence of strong electron-withdrawing groups attached to the arene. The overall transformation can be termed as a new example of a migratory cycloisomerization and, formally, it involves well-blended 1,2-iodine shift and hydroarylation steps.

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“…Along this line, we have recently communicated a traceless/modifiable silicon‐tethered pyridyldiisopropylsilyl (PyDipSi) directing group for the Pd‐catalyzed ortho ‐acyloxylation13 and ortho ‐halogenation14 reactions of aromatic and heteroaromatic CH bonds (Scheme ). These transformations allowed for efficient syntheses of the corresponding PyDipSi‐arenes in a highly regioselective mono‐functionalization fashion.…”

Section: Introductionmentioning

confidence: 99%

The Pyridyldiisopropylsilyl Group: A Masked Functionality and Directing Group for Monoselective ortho‐Acyloxylation and ortho‐Halogenation Reactions of Arenes

et al. 2011

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A novel, easily removable and modifiable silicon-tethered pyridyldiisopropylsilyl directing group for C–H functionalizations of arenes has been developed. The installation of the pyridyldiisopropylsilyl group can efficiently be achieved via two complementary routes using easily available 2-(diisopropylsilyl)pyridine (5). The first strategy features a nucleophilic hydride substitution at the silicon atom in 5 with aryllithium reagents generated in situ from the corresponding aryl bromides or iodides. The second milder route exploits a highly efficient room-temperature rhodium(I)-catalyzed cross-coupling reaction between 5 and aryl iodides. The latter approach can be applied to the preparation of a wide range of pyridyldiisopropylsilyl-substituted arenes possessing a variety of functional groups, including those incompatible with organometallic reagents. The pyridyldiisopropylsilyl directing group allows for a highly efficient, regioselective palladium(II)-catalyzed mono-ortho-acyloxylation and ortho-halogenation of various aromatic compounds. Most impor-tantly, the silicon-tethered directing group in both acyloxylated and halogenated products can easily be removed or efficiently converted into an array of other valuable functionalities. These transformations include protio-, deuterio-, halo-, boro-, and alkynyldesilylations, as well as a conversion of the directing group into the hydroxy functionality. In addition, the construction of aryl-aryl bonds via the Hiyama–Denmark cross-coupling reaction is feasible for the acetoxylated products. Moreover, the ortho-halogenated pyridyldiisopropylsilylarenes, bearing both nucleophilic pyridyldiisopropylsilyl and electrophilic aryl halide moieties, represent synthetically attractive 1,2-ambiphiles. A unique reactivity of these ambiphiles has been demonstrated in efficient syntheses of arylenediyne and benzosilole derivatives, as well as in a facile generation of benzyne. In addition, preliminary mechanistic studies of the acyloxylation and halogenation reactions have been performed. A trinuclear palladacycle intermediate has been isolated from a stoichiometric reaction between diisopropyl-(phenyl)pyrid-2-ylsilane (3a) and palladium acetate. Furthermore, both C–H functionalization reactions exhibited equally high values of the intramolecular primary kinetic isotope effect (kH/kD = 6.7). Based on these observations, a general mechanism involving the formation of a palladacycle via a C–H activation process as the rate-determining step has been proposed.

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A General Strategy Toward Aromatic 1,2‐Ambiphilic Synthons: Palladium‐Catalyzed ortho‐Halogenation of PyDipSi‐Arenes

Cited by 44 publications

References 51 publications

Room‐Temperature ortho‐Alkoxylation and ‐Halogenation of N‐Tosylbenzamides by Using Palladium(II)‐Catalyzed CH Activation

Room‐Temperature ortho‐Alkoxylation and ‐Halogenation of N‐Tosylbenzamides by Using Palladium(II)‐Catalyzed CH Activation

Gold(I)-catalyzed hydroarylation reaction of aryl (3-iodoprop-2-yn-1-yl) ethers: synthesis of 3-iodo-2H-chromene derivatives

The Pyridyldiisopropylsilyl Group: A Masked Functionality and Directing Group for Monoselective ortho‐Acyloxylation and ortho‐Halogenation Reactions of Arenes

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