A counteranion triggered arylation strategy using diaryliodonium fluorides

Chan, Louis K. M.; McNally, Andrew; Toh, Qiao Yan; Mendoza, Abraham; Gaunt, Matthew J.

doi:10.1039/c4sc02856b

Cited by 77 publications

(44 citation statements)

References 27 publications

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“…Generally,2 -phenyl-2-alkylcyanoacetates 4 were obtained in excellent yields of 77-92% when the Ro f1 is alkyl (Table 3, entries1-7). Among them, when Ri sf luoroalkyl or allyl, 4e and 4f can be furnished in good yields of 81% and7 7%, respectiviely.M oreover, when 1 bearing benzyla nd aromatic rings were employed,t he phenylated products 4h-4n were readily prepared in the good yields of 65-82% (Table 3, entries [8][9][10][11][12][13][14]. When Ro f1 is phenacyl, the phenylation product 4o was provided in am oderate yield of 45% (Table 3, entry 15).…”

Section: Resultsmentioning

confidence: 99%

“…[7] Very recently, Gaunt reported two cases of the fluoride counteranion within the diaryliodonium salts triggered C-arylation of a-cyano-a-phenyl esters in good yields under metal-freer eaction conditions. [8] In the context of our general interest in the synthesis of medically useful compounds by arylation of nucleophiles using iodoniums alts, we were intrigued by the possibility of metal-free arylation towards nitrile-containing 2-arylcyanoacetates.H erein we present the potassium tert-butoxide-mediated arylation of 2-substiuted cyanoacetates,g iving an efficienta ccess to 2-arylcyanoacetates.…”

Section: Introductionmentioning

confidence: 99%

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tert‐Butoxide‐Mediated Arylation of 2‐Substituted Cyanoacetates with Diaryliodonium Salts

2016

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

tert‐Butoxide‐Mediated Arylation of 2‐Substituted Cyanoacetates with Diaryliodonium Salts

2016

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“…Both allylic, benzylic alcohols and phenols were active in the reaction and were transformed to the appropriate arylated products with good to excellent yields. 17 A wide range of phenols (5) and diaryliodonium salts were compatible with this transformation which enabled a broad substrate scope of diaryl ethers (6) with high isolated yields (Scheme 4). The hydrogen bonding ability of fluoride enables the abstraction of proton, thus no additional strong base required for the transformation.…”

Section: Scheme 3 Preparation Of Diaryl Ethers By O-arylationmentioning

confidence: 99%

“…Sulfonic acids were also suitable starting materials for the appropriate sulfonester synthesis. 15 In the presence of a bulky base, sulfonic acids (17) could be transformed to the corresponding sulfonates (18) in a short reaction time in refluxing toluene (Scheme 9).…”

Section: Arylation Of Acidsmentioning

confidence: 99%

Diaryliodonium Salts in Organic Syntheses: A Useful Compound Class for Novel Arylation Strategies

Aradi

Tóth

Tolnai

et al. 2016

Synlett

193

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This account aims to give a description of the usefulness of diaryliodonium salts in organic chemistry, including their synthesis and applications in the presence and absence of transition metal catalysts. Herein, we briefly summarize the structural properties and reactivity of diaryliodonium salts. We collected several applications of the hypervalent reagents including metal-free arylations of C, O, N and S nucleophiles. Synthesis and functionalization of aromatic and heteroaromatic systems via copper and palladium catalyzed transformations are also discussed in this account.

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“…[15] Bromobenzene (3b)a nd 4-bromoiodobenzene (4b)were treated with mCPBAand TfOH to yield the symmetric 4-bromophenyl iodonium salt 1b in situ (Scheme 3a). Sodium nitrite and NaHCO 3 [19] were then added, thus providing nitroarene 2b and unreacted diaryliodonium salt as the major components.Addition of water [14d] and adjustment of the pH value improved the outcome,a nd delivered 2b in 58 %y ield with 3equivalents of NaNO 2 within 3hours. [8] Only the p-substituted product 2b was observed, and the complete regioselectivity can be attributed to the known, highly p-selective formation of diaryliodonium salts.…”

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confidence: 99%

One‐Pot C−H Functionalization of Arenes by Diaryliodonium Salts

2016

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Atransition-metal-free,mild, and highly regioselective synthesis of nitroarenes from arenes has been developed. The products are obtained in asequential 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,a nd constitutes an important step towards catalytic reactions with these hypervalent iodine reagents.Anefficient nitration of isolated diaryliodonium salts has also been developed, and the mechanismis proposed to proceed by a[ 2,2] ligand coupling pathway.Hypervalent iodine compounds have become important reagents for aw ide variety of transformations,a st hey have avaluable combination of properties including high reactivity, high functional-group tolerance,and low toxicity.[1] Themain drawback with hypervalent iodine reagents is the stoichiometric formation of either an iodine(I) or iodine(III) compound as waste,d epending on the oxidation state (III or V) of the starting reagent. This aspect lowers the atom efficiency and may lead to product purification problems.The groups of Ochiai and Kita reported the first catalytic uses of hypervalent iodine reagents in 2005 (Scheme 1a).[2] Since then many other systems have appeared, where ac atalytic amount of iodoarene is combined with as toichiometric amount of an oxidant.[3]Iodonium salts and their cyclic counterparts benziodoxol-(on)es (e.g. EBX and Tognis reagent) are important iodine(III) reagents for the transfer of carbon ligands (aryl, alkynyl, vinyl, CF 3 ,o rC Ng roups) to aw ide range of nucleophiles.[4] These reagents are generally synthesized in one or more steps,i solated, and subsequently reacted with an ucleophile.K ita and co-workers have demonstrated the efficient in situ formation of diaryliodonium salts from other iodine(III) reagents in metal-free arylations (Scheme 1b), [5] and the group of Suna has utilized the same strategy in metalcatalyzed arylations.[6] However,tothe best of our knowledge, catalytic reactions with iodonium salts or benziodoxol(on)es remain unknown. [4,7] In our long-term quest for catalytic arylation conditions, we reasoned that in situ formation of diaryliodonium salts from arenes and iodoarenes in the presence of an oxidant, followed by arylation of as uitable nucleophile under metalfree conditions,w ould constitute an important step towards this difficult goal. Herein we present our results of an efficient arylation of sodium nitrite with diaryliodonium salts,w hich can be formed in situ from arenes and iodoarenes under oxidative conditions (Scheme 1c). Them ethodology compares well to previous routes to nitroarenes,c oncerning regioselectivity,f unctional-group tolerance,a nd ease of handling. [8] Synthetic routes to aromatic nitro compounds are important, as nitroarenes are key intermediates in the preparation of many dyes,p lastics,a nd explosives.[9] They can be synthesized from arenes under harsh acidic conditions, [9a] by treatment with [bis(trifluoroacetoxy)iodo]benzene...

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A counteranion triggered arylation strategy using diaryliodonium fluorides

Abstract: A mild and transition metal-free counteranion triggered arylation strategy has been developed using diaryliodonium fluorides.

Cited by 77 publications

References 27 publications

tert‐Butoxide‐Mediated Arylation of 2‐Substituted Cyanoacetates with Diaryliodonium Salts

tert‐Butoxide‐Mediated Arylation of 2‐Substituted Cyanoacetates with Diaryliodonium Salts

Diaryliodonium Salts in Organic Syntheses: A Useful Compound Class for Novel Arylation Strategies

One‐Pot C−H Functionalization of Arenes by Diaryliodonium Salts

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