A mild carbon–boron bond formation from diaryliodonium salts

Miralles, N.; Romero, R. Martín; Fernández, Elena; Muñiz, Kilian

doi:10.1039/c5cc04944j

Cited by 60 publications

(35 citation statements)

References 53 publications

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“…2 Similar concepts of atom economy have been set out by Dauban and co-workers, who demonstrated a sequential oxidant / arylation role for ArI(OAc) 2,3 Muñiz who performed tandem borylation / Suzuki-Miyaura cross-coupling of diaryliodoniums, 4 and Jiang who described diaryl sulfide synthesis from a single iodonium species. 5 , 6 In each case (and, perforce, all intramolecular applications of cyclic diaryliodoniums) 7 the iodonium undergoes functionalization at the two ipso-positions.…”

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confidence: 88%

Domino N‐/C‐Arylation via In Situ Generation of a Directing Group: Atom‐Efficient Arylation Using Diaryliodonium Salts

et al. 2017

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Both aryl components of diaryliodonium salts can be used in a domino one-pot reaction via in situ generation of a directing group. A number of heterocycles undergo N-arylation which is followed by ruthenium-catalyzed C-arylation. Notably the reaction extends well to unsymmetrical diaryliodonium salts with a number of highly selective examples shown.Diaryliodonium salts have seen extensive application as arylating agents in recent years, as they possess desirable qualities of high reactivity, ease of use as stable, crystalline solids, and compatibility with a wide variety of metal catalysts. 1Their major drawback, however, is the generation of one equivalent of 'waste' aryl iodide in the vast majority of transformations, an unsustainable feature that limits future exploitation. We recently addressed this issue by capturing the generated aryl iodide in an iodonium arylation through a one-pot, tandem C-/ N-arylation of indole (Scheme 1A).2 Similar concepts of atom economy have been set out by Dauban and co-workers, who demonstrated a sequential oxidant / arylation role for ArI(OAc)2, 3 Muñiz who performed tandem borylation / Suzuki-Miyaura cross-coupling of diaryliodoniums, 4 and Jiang who described diaryl sulfide synthesis from a single iodonium species. 5 , 6 In each case (and, perforce, all intramolecular applications of cyclic diaryliodoniums) 7 the iodonium undergoes functionalization at the two ipso-positions. We were interested in developing alternative pathways to create new arylation patterns from iodoniums while preserving the atom-economic approach. Our plan is set out in Scheme 1B, which proposes a domino reaction whereby an intermediate generated in step one opens up new reactivity to harness the aryl iodide in step two: The Nheterocycle 1 can undergo arylation with 2 to give an N-aryl product 3, where the heterocycle can then act as a directing group for subsequent ortho C-H arylation taking place in situ with the released aryl iodide. Crucially, this second arylation breaks the symmetry of the starting iodonium, creating structures having greater diversity for application as building blocks in the chemical sciences.To develop the proposed sequence we required a heteroarene substrate offering versatile scope with respect to reaction conditions for the two arylations. Pyrazoles were appealing as they are known to react with iodoniums under both metal-catalyzed and metal-free conditions, 8 and functionalized pyrazoles have been extensively employed as privileged motifs in medicinal chemistry. 9 We elected to investigate rutheniumcatalysis for the key C-H arylation step, given the robust literature precedent, 10 the affordability of many Ru catalysts, 11 and our own recent experiences in developing Ru-catalyzed C-H functionalization chemistry. 12Scheme 1. Atom economical use of diaryliodoniums.Preliminary reaction screening of the two steps in isolation established that the first N-arylation step could be performed in a variety of solvents with 1.2 equivalents of diphenyliodonium triflate 2a...

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confidence: 88%

Domino N‐/C‐Arylation via In Situ Generation of a Directing Group: Atom‐Efficient Arylation Using Diaryliodonium Salts

et al. 2017

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“…In 2015, Muňiz and co‐workers reported a coupling reaction between diaryliodonium salts and bis(pinacolato)diboron (B 2 pin 2 ) under mild conditions to give aryl boronic esters and generate one equivalent of free aryl iodides (Scheme ) . The aryl boronic ester can then act as a partner for subsequent Suzuki–Miyaura cross‐coupling to take place in situ with the generated aryl iodide.…”

Section: Acyclic Diaryliodonium Saltsmentioning

confidence: 99%

“…In 2015, Muň iz and co-workersr eported ac oupling reaction between diaryliodonium salts and bis(pinacolato)diboron (B 2 pin 2 )u nder mild conditions to give aryl boronice sters and generate one equivalent of free aryl iodides (Scheme 6). [11] The aryl boronic ester can then act as ap artner for subsequent Suzuki-Miyaura cross-coupling to take place in situ with the generated aryl iodide. Differentk inds of symmetric diaryliodonium salts werec ompatible with the one-pot reaction system to provide the corresponding diaryl products exclusively.U nfortunately,t he example of the unsymmetric diaryliodonium salts was not afforded in this CÀCc oupling reaction of both aryl groups of the diaryliodonium reagent.…”

Section: Acyclic Diaryliodonium Saltsmentioning

confidence: 99%

Atom‐Economical Applications of Diaryliodonium Salts

Wang

Chen

Jiang

2018

Chemistry An Asian Journal

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Diaryliodonium salt, as a stable and easily prepared reagent, has become one of the most efficient arylation reagents in organic synthesis. In traditional methods, this reagent is generally applied as a single arylation source and the regenerated aryl iodide is a waste of resources. In the past five years, transition-metal-catalyzed utilization of both aryl groups in diaryliodonium salts has been well demonstrated. The purpose of the present review is to focus on various atom-economical applications of diaryliodonium salt methodologies that have been reported recently for the synthesis of functionalized molecules. The presentation is organized according to the structures of the diaryliodonium salts and the reaction components.

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“…Additionally, the in situ generated boronates could be directly arranged into Suzuki-Miyaura type cross-coupling reactions to produce biaryls in high yields.The great success of organylboronic acids and their derivatives in organic synthesis, [1] pharmaceuticals [2] and material chemistry [3] has inspired dramatic synthetic interests [4] on these privileged molecules. Thus, a range of protocols have been developed to convert aryl [5] and alkyl [6] halides, carboxylic acid derivatives, [7] anilines, [8] diaryliodonium salts, [9] arenes, [10] alkenes [11] and quaternary ammonium salts [12] etc. into boronic acids or their esters.…”

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confidence: 99%

Copper‐Catalyzed Monoorganylation of Trialkyl Borates with Functionalized Organozinc Pivalates

Gou

Shi

et al. 2018

ChemCatChem

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Organozinc pivalates, a recently developed air-and moisturestable organozinc species, were found for the first time as excellent organometallic species in the monoorganylation of trialkyl borates whereby boronic acids were prepared in high yields. The significant advantage of organozinc pivalates over another previously employed organometallic reagents, e. g., organolithium reagents, Grignard reagents and organozinc halides, is that the generation of multiorganylation byproducts such as borinic acids and trialkylboranes were completely suppressed. Additionally, the in situ generated boronates could be directly arranged into Suzuki-Miyaura type cross-coupling reactions to produce biaryls in high yields.The great success of organylboronic acids and their derivatives in organic synthesis, [1] pharmaceuticals [2] and material chemistry [3] has inspired dramatic synthetic interests [4] on these privileged molecules. Thus, a range of protocols have been developed to convert aryl [5] and alkyl [6] halides, carboxylic acid derivatives, [7] anilines, [8] diaryliodonium salts, [9] arenes, [10] alkenes [11] and quaternary ammonium salts [12] etc. into boronic acids or their esters. However, due to the employment of unaffordable expensive borylating agents or expensive transitional metal catalysts, most of these protocols are rarely employed in the practical boronic acids synthesis. Thus, the conventional approach, the electrophilic trapping of organometallics (generally the lithium reagents, [13] Grignard reagents [14] and organozinc reagents [15] ) with trialkyl borates, still occupies a large portion in modern factory manufacture. The common defects involved in this approach are, cryogenic conditions demanding, poor functional groups tolerance (largely due to high reactivity of organometallics), unavoidable borinic acid and borane byproducts (arise from second and third additions of the organometallic reagents into the borate esters), low isolated yields. To avoid multiple addition of organometallics to borate esters, Wang et al. [14d] reported that bis [2-(N,N-dimethylamino) ethyl] ether could be employed as a ligand to suppress these side reactions. Alternatively, Leermann et al. [14b] reported that excellent yields of boronic acids were obtained via reactions of Grignard's with B(OMe) 3 in the presence of LiCl.Organozinc pivalates [16] are a privileged class of organometallics particularly known to their air-and moisture-stability and broad spectrum of functional groups tolerance. These reagents exhibit excellent reactivity in reactions, e. g., Negishi cross coupling reactions [17] and were successfully used in the synthesis of complex molecules [18] Based on our interests on expanding the applicability of organozinc reagents in organic synthesis, [19] we here first describe a CuI-catalyzed chemospecific borylation of organozinc pivalates with trialkyl borates to afford boronic acids in high yields.Initially, p-TolZnBr·MgCl 2 ·LiCl (2a'), in situ prepared from ptolylbromide (1 a) via magnesium insertion-Z...

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A mild carbon–boron bond formation from diaryliodonium salts

Cited by 60 publications

References 53 publications

Domino N‐/C‐Arylation via In Situ Generation of a Directing Group: Atom‐Efficient Arylation Using Diaryliodonium Salts

Domino N‐/C‐Arylation via In Situ Generation of a Directing Group: Atom‐Efficient Arylation Using Diaryliodonium Salts

Atom‐Economical Applications of Diaryliodonium Salts

Copper‐Catalyzed Monoorganylation of Trialkyl Borates with Functionalized Organozinc Pivalates

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