An Efficient Procedure for the Synthesis of<i>ortho</i>-Trialkylsilylaryl Triflates: Easy Access to Precursors of Functionalized Arynes

Peña, Diego; Cobas, Agustín; Pérez, Dolores; Guitián, Enrique

doi:10.1055/s-2002-33110

Cited by 57 publications

(6 citation statements)

References 4 publications

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“…We questioned whether other strained π-bonds might also engage with BCBs, thus affording unique small-ring product architectures from these readily accessible building blocks. Here, we describe the strain-relief-driven Alder-ene reaction of polyfunctionalized BCBs with cyclopropenes, generated in situ from visible light-promoted decomposition of vinyl diazo compounds ( 2 , Figure b), to give cyclopropyl-substituted cyclobutenes ( 3 ); and also, the development of highly efficient ene reactions of BCBs with a selection of arynes generated under mild reaction conditions from arylsilane triflates 4 to give arylated cyclobutenes 5 . These reactions display a broad scope and high stereoselectivity; mechanistic studies support the involvement of an asynchronous concerted reaction pathway and highlight the importance of electronic effects in these transformations.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective Alder-Ene Reactions of Bicyclo[1.1.0]butanes: Facile Synthesis of Cyclopropyl- and Aryl-Substituted Cyclobutenes

Dasgupta,

Bhattacharjee,

Tong

et al. 2023

J. Am. Chem. Soc.

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Bicyclo[1.1.0]butanes (BCBs), strained carbocycles comprising two fused cyclopropane rings, have become well-established building blocks in organic synthesis, medicinal chemistry, and chemical biology due to their diverse reactivity profile with radicals, nucleophiles, cations, and carbenes. The constraints of the bicyclic ring system confer high p-character on the interbridgehead C−C bond, leading to this broad reaction profile; however, the use of BCBs in pericyclic processes has to date been largely overlooked in favor of such stepwise, non-concerted additions. Here, we describe the use of BCBs as substrates for ene-like reactions with strained alkenes and alkynes, which give rise to cyclobutenes decorated with highly substituted cyclopropanes and arenes. The former products are obtained from highly stereoselective reactions with cyclopropenes, generated in situ from vinyl diazoacetates under blue light irradiation (440 nm). Cyclobutenes featuring a quaternary aryl-bearing carbon atom are prepared from equivalent reactions with arynes, which proceed in high yields under mild conditions. Mechanistic studies highlight the importance of electronic effects in this chemistry, while computational investigations support a concerted pathway and rationalize the excellent stereoselectivity of reactions with cyclopropenes.

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Section: Introductionmentioning

confidence: 99%

Stereoselective Alder-Ene Reactions of Bicyclo[1.1.0]butanes: Facile Synthesis of Cyclopropyl- and Aryl-Substituted Cyclobutenes

Dasgupta,

Bhattacharjee,

Tong

et al. 2023

J. Am. Chem. Soc.

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“…Better results were obtained when 4 was subjected to a double bromodesilylation followed by nucleophilic substitution of one of the bromine atoms by methoxide to yield 5 . Subsequent treatment with BBr 3 afforded an unstable o ‐bromophenol, which was directly subjected to the protocol developed in our group for the synthesis of o ‐(trimethylsilyl)aryl triflates [22] to give 2 (route A in Scheme 2; six steps and 20.7% yield from 3 ).…”

Section: Resultsmentioning

confidence: 99%

Aryne‐Based Synthesis of Cyclobutadiene‐Containing Oligoacenes and Related Extended Biphenylene Derivatives

Álvarez,

Janeiro,

Cobas

et al. 2024

Adv Synth Catal

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Abstract. A previously undescribed aryne derived from a π‐extended biphenylene, 2,3‐didehydrobenzo[b]biphenylene, has been developed. The participation of this new aryne building block in [4+2] and palladium‐catalyzed [2+2+2] cycloaddition reactions has been applied to the synthesis of a variety of polycyclic conjugated hydrocarbons (PCHs) with appealing structures which combine (aromatic) benzene and (antiaromatic) cyclobutadiene (CBD) rings. Among them, a family of unsubstituted (or barely substituted) CBD‐oligoacenes has been accessed by iterative Diels‐Alder reactions of the new aryne with furans and/or isobenzofurans, followed by deoxygenative aromatization of the resulting epoxy‐derivatives. The experimental and computational studies of the newly synthesized PCHs suggest an important degree of electron delocalization along the polycyclic skeleton, more pronounced in the linearly fused derivatives. The computed ACID plots reveal clockwise current density vectors at the peripheral bonds, originating from the sigma contributions of the antiaromatic cyclobutadiene rings..

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“…Better results were obtained when 4 was subjected to a double bromodesilylation followed by nucleophilic substitution of one of the bromine atoms by methoxide to yield 5. Subsequent treatment with BBr3 afforded an unstable o-bromophenol, which was directly subjected to the protocol developed in our group for the synthesis of o-(trimethylsilyl)aryl triflates 22 to give 2 (route A in Scheme 2; six steps and 20.7% yield from 3). Alternatively, the Co(I)-catalyzed [2+2+2] cycloaddition of 3 with the trimethylsilyl alkynylboronate 6 23 afforded 7 in 40% yield.…”

Section: Resultsmentioning

confidence: 99%

Aryne-based synthesis of cyclobutadiene-containing oligoacenes and related extended biphenylene derivatives

Álvarez,

Janeiro,

Cobas

et al. 2023

Preprint

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A novel aryne derived from a π-extended biphenylene, 2,3-didehydrobenzo[b]biphenylene, has been developed. The participation of this new aryne building block in [4+2] and palladium-catalyzed [2+2+2] cycloaddition reactions has been effectively applied to the synthesis of a variety of polycyclic conjugated hydrocarbons (PCHs) with appealing structures which combine (aromatic) benzene and (antiaromatic) cyclobutadiene (CBD) rings. Among them, a family of unsubstituted (or barely substituted) CBD-oligoacenes has been accessed by iterative Diels-Alder reactions of the new aryne wit furans and/or isobenzofurans, followed by deoxygenative aromatization of the resulting epoxy-derivatives. The experimental and computational study of the newly synthesized PCHs suggests an important degree of electron delocalization along the polycyclic skeleton, more pronounced in the linearly fused derivatives. Interestingly, the computed ACID plots reveal clockwise current density vectors at the peripheral bonds, originating from the sigma contributions of the antiaromatic cyclobutadiene rings.

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An Efficient Procedure for the Synthesis ofortho-Trialkylsilylaryl Triflates: Easy Access to Precursors of Functionalized Arynes

Abstract: o-Trialkylsilylaryl triflates, which are useful aryne precursors, are prepared from o-bromophenols by an efficient, one-pot procedure involving O-silylation, metal-halogen exchange, O-to C-silyl migration, and entrapment of the phenoxide with triflic anhydride.

Cited by 57 publications

References 4 publications

Stereoselective Alder-Ene Reactions of Bicyclo[1.1.0]butanes: Facile Synthesis of Cyclopropyl- and Aryl-Substituted Cyclobutenes

Stereoselective Alder-Ene Reactions of Bicyclo[1.1.0]butanes: Facile Synthesis of Cyclopropyl- and Aryl-Substituted Cyclobutenes

Aryne‐Based Synthesis of Cyclobutadiene‐Containing Oligoacenes and Related Extended Biphenylene Derivatives

Aryne-based synthesis of cyclobutadiene-containing oligoacenes and related extended biphenylene derivatives

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