Chemoselective palladium-catalyzed deprotonative arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers

Gao, Feng; Kim, Byeong-Seon; Walsh, Patrick J.

doi:10.1039/c5sc02739j

Cited by 27 publications

(11 citation statements)

References 97 publications

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“…Subsequent studies by the same group have identified (again) CPME as the solvent of choice for the first chemoselective tandem C(sp 3 )−H arylation/[1,2]‐Wittig rearrangement of pyridylmethyl ethers under Pd‐catalysis conditions (Scheme ) . Optimization studies have revealed the critical role played by the base/solvent/temperature and have thus allowed the design of a divergent synthesis of tertiary and quaternary adducts.…”

Section: Synthetic Applicationsmentioning

confidence: 99%

“…Subsequents tudies by the same group have identified (again) CPME as the solvent of choice for the first chemoselective tandem C(sp 3 )ÀHa rylation/[1,2]-Wittig rearrangemento fp yridylmethyl ethers under Pd-catalysis conditions (Scheme 18). [36] Optimization studies have revealed the critical role playedb yt he base/solvent/temperature andh ave thus allowed the design of ad ivergent synthesis of tertiary and quaternary adducts. Accordingly,t he tandem process becomes highly selective by selecting the LiN(TMS) 2 /CPME/45 8Ct riad, whereas the corresponding sodium base in DME at 23 8Cf urnishes the simplea rylated product.…”

Section: Use Of Cpme In Transition-metal-catalyzed Chemistrymentioning

confidence: 99%

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Cyclopentyl Methyl Ether: An Elective Ecofriendly Ethereal Solvent in Classical and Modern Organic Chemistry

et al. 2018

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Solvents represent one of the major contributions to the environmental impact of fine‐chemical synthesis. As a result, the use of environmentally friendly solvents in widely employed reactions is a challenge of vast real interest in contemporary organic chemistry. Within this Review, a great variety of examples showing how cyclopentyl methyl ether has been established as particularly useful for this purpose are reported. Indeed, its low toxicity, high boiling point, low melting point, hydrophobicity, chemical stability towards a wide range of conditions, exceptional stability towards the abstraction of hydrogen atoms, relatively low latent heat of vaporization, and the ease with which it can be recovered and recycled enable its successful employment as a solvent in a wide range of synthetic applications, including organometallic chemistry, catalysis, biphasic reactions, oxidations, and radical reactions.

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Section: Synthetic Applicationsmentioning

confidence: 99%

Section: Use Of Cpme In Transition-metal-catalyzed Chemistrymentioning

confidence: 99%

Cyclopentyl Methyl Ether: An Elective Ecofriendly Ethereal Solvent in Classical and Modern Organic Chemistry

et al. 2018

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“…We are interested in alternative strategies to selectively arylate weakly acidic (p K a 25–35) benzylic C–H bonds of arenes and heteroarenes. − Our strategy relies on reversible deprotonation of the C–H bonds of the benzylic pronucleophile in the presence of the catalyst, which then arylates the substrate. A limitation of this approach is that some benzylic C–H bonds, such as those in toluene, have such high p K a values (∼43 for toluene in DMSO) that appreciable deprotonation in the presence of a transition metal catalyst is difficult.…”

Section: Introductionmentioning

confidence: 99%

Cation−π Interactions in the Benzylic Arylation of Toluenes with Bimetallic Catalysts

Sha

Tcyrulnikov

et al. 2018

J. Am. Chem. Soc.

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A method to directly arylate toluene derivatives with aryl bromides to generate diarylmethanes, which are important building blocks in drug discovery, is described. In this method, KN(SiMe) in combination with a (NIXANTPHOS)Pd catalyst accomplished the deprotonative activation of toluene derivatives to permit cross-coupling with aryl bromides. Good to excellent yields are obtained with a range of electron-rich to neutral aryl bromides. Both electron-rich and electron-poor toluene derivatives are well tolerated, and even 2-chlorotoluene performs well, providing a platform for introduction of additional functionalization. This discovery hinges on the use of a main group metal to activate toluene for deprotonation by means of a cation-π interaction, which is secured by a bimetallic K(NIXANTPHOS)Pd assembly. Mechanistic and computational studies support acidification of toluene derivatives by the K-cation- π interaction, which may prove pertinent in the development of other, new reaction systems.

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“…These reactions involve a weakly acidic C–H of the substrate (pronucleophile) that is reversibly deprotonated under the reaction conditions. Subsequently, the nucleophile undergoes catalyst promoted arylation 33 34 35 36 or vinylation 37 . This method has been particularly successful with the generation of triarylmethanes 38 39 40 .…”

Section: Discussionmentioning

confidence: 99%

Palladium-catalysed synthesis of triaryl(heteroaryl)methanes

Zhang

Kim

et al. 2017

Nat Commun

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Tetraarylmethane derivatives are desirable for a variety of applications, but difficult to access with modern C–C bond-forming reactions. Here we report a straightforward method for palladium-catalysed arylation of aryl(heteroaryl)methanes and diaryl(heteroaryl)methanes with aryl chlorides. This reaction enables introduction of various aryl groups to construct triaryl(heteroaryl)methanes via a C–H functionalization in good to excellent yield, and represents the first step towards a general transition metal catalysed synthesis of tetraarylmethanes.

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Chemoselective palladium-catalyzed deprotonative arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers

Abstract: Control of chemoselectivity is one of the most challenging problems facing chemists and is particularly important in the synthesis of bioactive compounds and medications.

Cited by 27 publications

References 97 publications

Cyclopentyl Methyl Ether: An Elective Ecofriendly Ethereal Solvent in Classical and Modern Organic Chemistry

Cyclopentyl Methyl Ether: An Elective Ecofriendly Ethereal Solvent in Classical and Modern Organic Chemistry

Cation−π Interactions in the Benzylic Arylation of Toluenes with Bimetallic Catalysts

Palladium-catalysed synthesis of triaryl(heteroaryl)methanes

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