High Temperature Bromination. 7.<sup>1</sup> Bromination of Norbornadiene

Tutar, Ahmet; Taşkesenligil, Yavuz; Çakmak, Osman; Abbasoǧlu, and Riza; Balcı, Metin

doi:10.1021/jo960225l

Cited by 44 publications

(28 citation statements)

References 15 publications

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“…6 The subsequent photobrominations were performed in CCl 4 by irradiation with a projector lamp (250 W, visible light) in an immersion photochemical apparatus. 7…”

Section: H I G H L Y B R O M I N a T E D N O R B O R N A N E S B Y P mentioning

confidence: 99%

“…6 It was our intention to employ the exhaustive photobromination of norbornadiene to obtain still higher brominated norbornanes and norbornadienes. Presently, we report an effective and convenient procedure for the synthesis of 2,3,5,6-tetrabromonorbornadiene and demonstrate its value as precursor to the corresponding tetramethoxy-substituted derivative.…”

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confidence: 99%

“…6 The subsequent photobrominations were performed in CCl 4 by irradiation with a projector lamp (250 W, visible light) in an immersion photochemical apparatus. 7 The photobromination of the diastereomeric mixture of 3,5-dibromonortricyclane 2 with one or two equivalents of bromine at room temperature in CCl 4 resulted in a complex reaction mixture, which could not be separated by silica-gel chromatography.…”

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Highly Brominated Norbornanes by Photobromination as Precursors for the Convenient Synthesis of 2,3,5,6-Tetrabromo- and 2,3,5,6-Tetramethoxy-substituted Norbornadienes

Adam¹,

Çakmak²,

Saha‐Möller³

et al. 2002

Synlett

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H i g h l y b r o m i n a t e d N o r b o r n a n e s b y P h o t o b r o m i n a t i o nAbstract: An efficient synthesis is described for hexabromonorbornane by photobromination of norbornadiene. Double dehydrobromination of the hexabromide by t-BuOK affords in high yield 2,3,5,6-tetrabromonorbornadiene, its copper-assisted treatment with sodium methoxide leads to the 2,3,5,6-tetramethoxy derivative. The tetrabromide constitutes a valuable precursor for the preparation of functionalized tetrasubstituted norbornadienes.When norbornadiene is converted photochemically to the higher-energy quadricyclane, the stored energy may be released by reverting catalytically the strained quadricyclane to its norbornadiene. Since norbornadiene itself does not undergo efficient valence isomerization upon direct and/or sensitized irradiation, norbornadienes with appropriate chromophores have been synthesized and their photoisomerization examined. 1 In this context, tetrasubstituted norbornadienes have attracted considerable attention because their quadricyclanes may serve as potential solar-energy storage cells, but a convenient preparation of such norbornadienes is still lacking. 2 In particular, the 2,3,5,6-tetrasubstituted norbornadienes should be of interest, but their preparation has been to date quite difficult. In addition, substituted norbornadienes have served as key intermediates in the synthesis of natural products such as the prostaglandin endoperoxides PGH 2 and PGG 2 , 3 cis-trikentrin, 4 and B-santalol. 5Most literature syntheses of 2,3,5,6-tetrasubstituted norbornadienes rely on the Diels-Alder reaction between cyclopentadienes and highly activated acetylenes. Unactivated acetylenes are poor dienophiles, which limits the type of norbornadienes accessible by this method to derivatives with electron-withdrawing groups.Recently, we have succeeded in the preparation of 2,3,5,6-tetrabromonorbornane 3 by the selective bromination of norbornadiene 1 and we have developed a synthetic method for dibromonorbornadienes by dehydrobromination of the tetrabromide 3. 6 It was our intention to employ the exhaustive photobromination of norbornadiene to obtain still higher brominated norbornanes and norbornadienes. Presently, we report an effective and convenient procedure for the synthesis of 2,3,5,6-tetrabromonorbornadiene and demonstrate its value as precursor to the corresponding tetramethoxy-substituted derivative.The bromination of norbornadiene at the reflux temperature of CCl 4 afforded the two diastereomeric 3,5-dibromonortricyclanes 2 and the three diastereomeric 2,3,5,6-tetrabromonorbornanes 3, which were readily separated by fractional distillation in 40% and 54% yields (Scheme). 6 The subsequent photobrominations were performed in CCl 4 by irradiation with a projector lamp (250 W, visible light) in an immersion photochemical apparatus. 7The photobromination of the diastereomeric mixture of 3,5-dibromonortricyclane 2 with one or two equivalents of bromine at room temperature in CCl 4 resulted in a complex reaction mixtu...

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“…6 The subsequent photobrominations were performed in CCl 4 by irradiation with a projector lamp (250 W, visible light) in an immersion photochemical apparatus. 7…”

Section: H I G H L Y B R O M I N a T E D N O R B O R N A N E S B Y P mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Highly Brominated Norbornanes by Photobromination as Precursors for the Convenient Synthesis of 2,3,5,6-Tetrabromo- and 2,3,5,6-Tetramethoxy-substituted Norbornadienes

Adam¹,

Çakmak²,

Saha‐Möller³

et al. 2002

Synlett

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“…In connection with our continuing work in the temperature bromination reactions we have been interested in the bromination reaction of norbornadiene at room and at high temperature in order to see the effect of the temperature on skeletal rearrangement [5], Recently we presented on alternative large-scale preparation of 2,5-dibromonorbornadiene by high temperature bromination of norbornadiene at 350 K in CCU followed by dehydrobromination of nonrearranged addition products [6].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of 2,2-exo-3,5,5-exo-6-hexabromobicycloheptane, C7H6Br6

Akkurt

Çeli̇k

Tutar

et al. 2000

Zeitschrift Für Kristallographie - New Crystal Structures

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C7H 6 Br 6 , monoclinic, Pl2ilnl (No. 14), a = 7.2717(7) A, b = 17.152(2) A, c = 10.0043(7) Â, (3 = 97.722(7)°, V = 1236.5 A 3 , Z = 4, R gt (F) = 0.086, wR obs (F 2 ) = 0.227, 7=293 K.Source of material 2,5-dibromonorbornadiene was brominated at high temperature. After reaction we isolated the title compound by fractional crystallization. It was dissolved in boiling carbontetrachloride. The clear solution was cooled slowly to room temperature. In about 12 h, colorless rod-shaped crystals were obtained. DiscussionConstitution and configuration of the products formed by electrophilic addition to norbornane and norbornadienes are interesting [1][2][3][4]. In connection with our continuing work in the temperature bromination reactions we have been interested in the bromination reaction of norbornadiene at room and at high temperature in order to see the effect of the temperature on skeletal rearrangement [5], Recently we presented on alternative large-scale preparation of 2,5-dibromonorbornadiene by high temperature bromination of norbornadiene at 350 K in CCU followed by dehydrobromination of nonrearranged addition products [6].The topology of the norbornane moities in the title compound is consistent with that reported in other norboraanes. In particular, as observed in other norbornane derivatives (93.3 (8)

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“…Light yellow liquid. (22). Into a 50 mL, two-necked, round-bottomed flask were placed Pd/C (10.0%) (100 mg) catalyst and of 22 (1.0 g, 7.56 mmol) in MeOH (20 mL).…”

Section: Reduction Of 23-dihydro-1h-indene (7)mentioning

confidence: 99%

High temperature bromination Part XXIII: Bromination of octahydro-1H-indene and octahydro-1H-4,7-methanoindene

Özer¹,

Kılbaş²,

Balcı³

2013

Arkivoc

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Thermal and photobromination of octahydro-1H-indene and octahydro-1H-4,7-methanoindene were investigated. Three isomeric tetrabromides (1,3,4,7-tetrabromo-2,3,4,5,6,7-hexahydro-1H-indene) were formed along with a smaller amount of tribromoindane and a pentabromide by thermal bromination of octahydro-1H-indene. The thermodynamically most stable isomers were formed. Morover, thermal and photochemical bromination of octahydro-1H-4,7-methanoindene furnished bromides resulting regiospecifically from the allylic bromination of the five-membered ring. Furthermore, the double bond formed as the intermediate functional group was also brominated due to its pyramidalization. The mechanism proposed for the formation of product distribution was discussed.

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High Temperature Bromination. 7.¹ Bromination of Norbornadiene

Cited by 44 publications

References 15 publications

Highly Brominated Norbornanes by Photobromination as Precursors for the Convenient Synthesis of 2,3,5,6-Tetrabromo- and 2,3,5,6-Tetramethoxy-substituted Norbornadienes

Highly Brominated Norbornanes by Photobromination as Precursors for the Convenient Synthesis of 2,3,5,6-Tetrabromo- and 2,3,5,6-Tetramethoxy-substituted Norbornadienes

Crystal structure of 2,2-exo-3,5,5-exo-6-hexabromobicycloheptane, C7H6Br6

High temperature bromination Part XXIII: Bromination of octahydro-1H-indene and octahydro-1H-4,7-methanoindene

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High Temperature Bromination. 7.1 Bromination of Norbornadiene

Cited by 44 publications

References 15 publications

Highly Brominated Norbornanes by Photobromination as Precursors for the Convenient Synthesis of 2,3,5,6-Tetrabromo- and 2,3,5,6-Tetramethoxy-substituted Norbornadienes

Highly Brominated Norbornanes by Photobromination as Precursors for the Convenient Synthesis of 2,3,5,6-Tetrabromo- and 2,3,5,6-Tetramethoxy-substituted Norbornadienes

Crystal structure of 2,2-exo-3,5,5-exo-6-hexabromobicycloheptane, C7H6Br6

High temperature bromination Part XXIII: Bromination of octahydro-1H-indene and octahydro-1H-4,7-methanoindene

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High Temperature Bromination. 7.¹ Bromination of Norbornadiene