Metallic nickel-assisted room-temperature generation and Diels-Alder chemistry of o-xylylene intermediates

Inaba, Shin-ichi; Wehmeyer, R. M.; Forkner, Matthew W.; Rieke, Reuben D.

doi:10.1021/jo00237a022

Cited by 53 publications

(14 citation statements)

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“…The dibromo precursor 2 was made by the reaction of N-bromosuccinimide with indan [6]. Treatment of 2 with LiPPh 2 did not give anphos and the only detected product was Ph 2 PH.…”

Section: Resultsmentioning

confidence: 99%

Chelates formed by a constrained bis(diphenylphosphino)xylene; the crystal structures of [FeCl2(anphos)] and [RhCl(CO)(anphos-monoxide)]

Higham¹,

Middleton²,

Heslop³

et al. 2004

Journal of Organometallic Chemistry

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“…The dibromo precursor 2 was made by the reaction of N-bromosuccinimide with indan [6]. Treatment of 2 with LiPPh 2 did not give anphos and the only detected product was Ph 2 PH.…”

Section: Resultsmentioning

confidence: 99%

Chelates formed by a constrained bis(diphenylphosphino)xylene; the crystal structures of [FeCl2(anphos)] and [RhCl(CO)(anphos-monoxide)]

Higham¹,

Middleton²,

Heslop³

et al. 2004

Journal of Organometallic Chemistry

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“…Preparation of the title benzocyclooctenedione has been reported [ 5 ], but the authors did not publish any experimental details. Our synthetic scheme began with the known diester 1 , which was prepared by a literature procedure [ 6 ] from the Diels-Alder reaction between diethyl fumarate and an o -xylylene intermediate [ 7 ], which has been obtained in turn by 1,4-dehalogenation of α,α / -dibromo- o -xylene in the presence of highly reactive metallic nickel.…”

Section: Resultsmentioning

confidence: 99%

Isolation and Characterization of Silyl Enol Ether Intermediates in the Synthesis of 5,6,9,10–Tetrahydro-7,8-benzocyclooctenedione

Fakhri

Zenouz

2002

Molecules

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“…This compound is stable in a freezer for a few months and in CH 2 Cl 2 solution at r.t. for at least several weeks. *,3S*)-1,2,3,4-Tetrahydronaphthalene-2,3-dicarboxylate (3a); 5 Typical Procedure To a solution of 2 (136 mg, 0.50 mmol) in MeCN (1.0 mL) were added dimethyl fumarate (144 mg, 1.0 mmol), KF (58 mg, 1.0 mmol), and 18-crown-6 (13 mg, 0.050 mmol). The mixture was stirred for 42 h at r.t. and then it was poured into H 2 O (40 mL), extracted with CH 2 Cl 2 (3 × 30 mL), dried (anhyd Na 2 SO 4 ), and concentrated in vacuo.…”

Section: -[(Trimethylsilyl)methyl]benzyl Methanesulfonate (2)mentioning

confidence: 99%

2-[(Trimethylsilyl)methyl]benzyl Methanesulfonates: Useful Precursors for the Generation of o-Quinodimethanes

Sano¹

2014

Synthesis

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2-[(Trimethylsilyl)methyl]benzyl methanesulfonates react with potassium fluoride in the presence of a catalytic amount of 18-crown-6 at room temperature to give o-quinodimethanes, which are trapped with electron-deficient olefins to afford [4+2] cycloadducts in good yields.The Diels-Alder reaction of o-quinodimethane intermediates with alkenes is a versatile method for the synthesis of 1,2,3,4-tetrahydronaphthalene structures. Various methods for the generation of o-quinodimethanes have been developed, and these have been applied to the syntheses of natural products such as steroids. 1 Among them, 1,4-elimination in α′-heterosubstituted α-silyl-o-xylenes is a useful method for the generation of o-quinodimethanes under mild conditions compared with other methods. 2 However, some problems remain with this type of reaction; the precursors are difficult or troublesome to prepare and somewhat harsh conditions are required to generate the oquinodimethane intermediate in some cases. For example, it has been reported that 2-[(trimethylsilyl)methyl]benzyl acetate and the corresponding phenyl carbonate can be prepared in short steps, and the o-quinodimethane can be generated under thermal conditions using potassium fluoride (DMF, 100 °C) or potassium fluoride with an equimolar amount of 18-crown-6 (MeCN, 35-50 °C). 2g-j We envisioned that the silyl compound, which has a better leaving group than the ester or carbonate group, would generate the o-quinodimethane under milder conditions. In this study, we aimed to develop a new precursor, which can be prepared in short steps, and generate o-quinodimethane under mild conditions; we expected that 2-[(trimethylsilyl)methyl]benzyl methanesulfonate (2) would meet these requirements. 3In our preliminary experiment, we found that 2, which was derived from the corresponding alcohol 1, 2f reacts with two equivalents of potassium fluoride in the presence of 30 mol% of 18-crown-6 to give spiro-di-o-xylylene 4 in 68% yield (NMR) with a small amount of [4+4] cycloadduct of o-quinodimethane 5 (6%), 4 indicating that 2 works as a precursor of o-quinodimethane in the presence of a fluoride source (Scheme 1). Intermolecular cycloaddition of o-quinodimethane generated from 2 with electron-deficient olefins could be performed to give tetrahydronaphthalenes 3. We examined the reaction of 2 with dimethyl fumarate as a typical dienophile in the presence of potassium fluoride in acetonitrile at room temperature to optimize the reaction conditions (Table 1). Scheme 1

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Metallic nickel-assisted room-temperature generation and Diels-Alder chemistry of o-xylylene intermediates

Cited by 53 publications

References 0 publications

Chelates formed by a constrained bis(diphenylphosphino)xylene; the crystal structures of [FeCl2(anphos)] and [RhCl(CO)(anphos-monoxide)]

Chelates formed by a constrained bis(diphenylphosphino)xylene; the crystal structures of [FeCl2(anphos)] and [RhCl(CO)(anphos-monoxide)]

Isolation and Characterization of Silyl Enol Ether Intermediates in the Synthesis of 5,6,9,10–Tetrahydro-7,8-benzocyclooctenedione

2-[(Trimethylsilyl)methyl]benzyl Methanesulfonates: Useful Precursors for the Generation of o-Quinodimethanes

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