Bromination of octmethylcyclopentene - the irregular reactivity of a sterically hindered cycloalkene

Mayr, Herbert; Will, Elfriede; Heigl, Ulrich W.; Schade, Christian

doi:10.1016/0040-4020(86)80016-3

Cited by 13 publications

(9 citation statements)

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“…The selection of bromo-organic compounds in this work is based primarily on their potential for bromination reactions. This work summarizes the applications of the following bromo-organic compounds in organic synthetic transformations: (1) Nbromosuccinimide, (2) ammonium bromide, (3) N-bromoacetamide, (4) bis(dimethylacetamide) hydrogen dibromobromate, (5) benzalkonium tribromide (6) 1-benzyl-4-aza-1azoniabicyclo[2.2.2]octane tribromide, (7) benzimidazolium bromochromate, (8) benzyltriethylammonium tribromide, (9) benzyltrimethylammonium tribromide, (10) benzyltriphenylphosphonium tribromide, (11) bromamine-T, (12) Nbromobenzamide (benzbromamide), ( 13) N-bromo-tert-butylamine, ( 14) 2-bromo-2-cyano-N,N-dimethylacetamide, (15) bromodichloroisocyanuric acid, ( 16) 1-bromo-5,5-diethylbarbituric acid and 1,3-dibromo-5,5-diethylbarbituric acid, (17) bromodimethylsulfonium bromide, (18) 3-bromo-4,4-dimethyl-2-oxazolidinone, (19) 3-bromo-5,5-dimethylhydantoin, (20) 3-bromo-3-(ethoxycarbonyl)-2,4-dioxo-1,2,3,4-tetrahydroquinones, (21) bromonitromethane, ( 22) N-bromophthalimide, (23) N-bromosaccharin, (24) (tert-butylamino)triphenylphosphonium tribromide, (25) tert-butyl N,N-dibromocarbamate, (26) 1-butyl-3-methylimidazolium tribromide, (27) 1-butyl-3methylpyridinium tribromide, (28) bromine supported on resin, (29) carbon tetrabromide, (30) cetylpyridinium tribromide, (31) cetyltrimethylammonium tribromide, (32) chiral brominating agent, (33) cross-linked poly(vinylpyridinium hydrobromide perbromide) resins, (34) crown ether complex of molecular bromine, (35) Apart from the above bromo-organic compounds, we also discuss herein the use of different nonmetallic as well as naturally occurring bromo compounds in synthetic organic transformations: (109) HOBr, (110) phosphorus oxybromide, (111) iodine monobromide, (112) boron tribromide, (113) bromine chloride, (114) thionyl bromide, (115) bromine fluoride, (116) bromine trifluoride, (117) HBr, (118) bromoiodinanes, (119) alkyl hypobromites...…”

Section: Scope Of This Reviewmentioning

confidence: 99%

“…32 Mayr et al brominated octamethylcyclopentene under mild conditions with Br 2 in CCl 4 at 20 °C. 33 Zabicky et al carried out the reaction of bromine and cyclohexene in aqueous media and studied the selectivity of bromohydrin vs dibromo adduct formation. Olefin suspensions in water yield mainly the dibromo adduct when treated with neat liquid Br 2 , or bromohydrin when treated with aquous Br 2 .…”

Section: Bromination Reactions 31 Bromination With Molecular Brominementioning

confidence: 99%

“…Bromination of 4-cyclohexene-1,2-dicarboximides by bromine in CHCl 3 for 1.5 h at 60–62 °C produced dibromo derivatives and tetrabromo derivatives . Mayr et al brominated octamethylcyclopentene under mild conditions with Br 2 in CCl 4 at 20 °C . Zabicky et al carried out the reaction of bromine and cyclohexene in aqueous media and studied the selectivity of bromohydrin vs dibromo adduct formation.…”

Section: Bromination Reactionsmentioning

confidence: 99%

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Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

2016

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Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

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Section: Scope Of This Reviewmentioning

confidence: 99%

Section: Bromination Reactions 31 Bromination With Molecular Brominementioning

confidence: 99%

Section: Bromination Reactionsmentioning

confidence: 99%

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Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

2016

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“…In any case sterically crowded, intermediate bromonium ions eliminate a proton either from the β ‐position, observed in alkenes 1 – 3 ,11–13 or from the α ‐position observed in compound 4 14…”

Section: Influence Of Steric and Polar Effects On Reaction Rates And mentioning

confidence: 97%

“…Alkenes that lead to products resulting from addition–elimination : Steric bulk by alkyl groups in special tetrasubstituted alkenes like octamethylcyclopentene ( 1 ),11 tetraisobutylethene ( 2 ),12 ( E )‐2,2,3,4,5,5‐hexamethylhex‐3‐ene ( 3 ),13 and tri‐ tert ‐butylbuta‐1,3‐diene ( 4 )14 results in addition–elimination as a consequence of treatment with equimolar amounts of bromine; this is because the hypothetical 1,2‐dibromide is sterically too strained to be formed…”

Section: Influence Of Steric and Polar Effects On Reaction Rates And mentioning

confidence: 99%

What is the Nature of the First‐Formed Intermediates in the Electrophilic Halogenation of Alkenes, Alkynes, and Allenes?

Lenoir¹,

Chiappe

2003

Chemistry A European J

104

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The pi complexes first formed as essential intermediates from alkenes, alkynes, and allenes with bromine have been investigated in different solvents by UV-spectroscopy in combination with stopped-flow techniques allowing the determination of the equilibrium constants, K(f). Using alkenes with sterically protected double bonds, such as di-tert-butylstilbene and tetraneopentylethylene, the reaction stops at the stage of the 1:1 and 1:2 pi complex of the alkene with bromine as persistent species in 1,2-dichlorethane as solvent. Calculations by state-of-art ab initio and DFT methods reproduces the experimentally determined thermodynamic values quite well, and reveal the preferred structures and nature of both complexes for ethene, ethyne, and allene. Consideration of the entropy term reveals that complexes are stabilized in solution owing to reduction of the entropy loss by restricted translations and rotation. According to calculations these species are Mulliken-outer-type complexes with no or little charge transfer from bromine to the double or triple bond, respectively. The 1:2 complex has a close structural relationship to the bromonium- or bromirenium ion, which is the subsequent intermediate on the reaction coordinate. Steric influences show a strong effect on the K(f) value, which can be explained by the polarizibility of the parent system. Addition-elimination often occurs. In bromination of adamantylidenadamantane and its derivatives the reaction stops at the stage of the bromonium ion. The effect of various polar groups situated in equatorial homoallyl positions on the stability of corresponding pi complex and bromonium ion has been studied in this series.

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Synthesis and Structure of 1,2‐Dimethylene[2.10]metacyclophane and Its Conversion into Chiral [10]Benzenometacyclophanes

et al. 2017

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Bromination of 5,21‐di‐tert‐butyl‐8,24‐dimethoxy‐1,2‐dimethyl[2.10]metacyclophan‐1‐ene (MCP‐1‐ene; 1) with benzyltrimethylammonium tribromide exclusively afforded 1,2‐bis(bromomethyl)‐5,21‐di‐tert‐butyl‐8,24‐dimethoxy[2.10]MCP‐1‐ene (2). Debromination of 2 with Zn and AcOH in CH2Cl2 solution at room temperature for 24 h produced dimethylene[2.10]MCP 7 in 92 % yield, which is a stable solid compound. Compound 7 was treated with dimethyl acetylenedicarboxylate (DMAD) to provide 1,2‐(3′,6′‐dihydrobenzo)‐5,21‐di‐tert‐butyl‐8,24‐dimethoxy[2.10]MCP‐4′,5′‐dimethylcarboxylate (8) in good yield. Diels–Alder adduct 8 was converted into a novel and inherently chiral areno‐bridged dimethoxy[2.10]MCP‐4′,5′‐dimethylcarboxylate 9, possessing C1 symmetry, by aromatization with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ). A new type of N‐phenyl‐maleimide substituted 1,2‐(3′,6′‐dihydrobenzo)‐5,21‐di‐tert‐butyl‐8,24‐dimethoxy[2.10]MCP‐4′,5′‐N‐phenylmaleimide 10 was also synthesized from 7 through treatment with N‐phenylmaleimide in toluene at 110 °C followed by aromatization with DDQ. Single‐crystal X‐ray analysis of 9 revealed the formation of a syn‐isomer.

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Bromination of octmethylcyclopentene - the irregular reactivity of a sterically hindered cycloalkene

Cited by 13 publications

References 9 publications

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

What is the Nature of the First‐Formed Intermediates in the Electrophilic Halogenation of Alkenes, Alkynes, and Allenes?

Synthesis and Structure of 1,2‐Dimethylene[2.10]metacyclophane and Its Conversion into Chiral [10]Benzenometacyclophanes

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