cas 1192-04-7, 1-Bromo-1-cyclopentene | Articles data

Articles about 1192-04-7Total 10 be found

A Simple Preparation of Cyclic Vinylic Bromides (1-Bromocycloalkenes and 1-Bromo-1,5-cyclooctadiene) from 1,2-Dibromocycloalkanes
1,2-Dibromocyclopentane, 1,2-dibromocyclohexane, 1,2-dibromocycloheptane, 1,2-dibromocyclooctane, 1,2-dibromocyclododecane, and 5,6-dibromocyclooctene are smoothly dehydrobrominated to the corresponding 1-bromocycloalkenes in good yield using morpholine and dimethyl sulfoxide in benzene or ethanol.
Bandodakar, Balachandra S.,Nagendrappa, Gopalpur
p. 843 - 844
(1990)
Read Online

Copper-Catalyzed C?P Cross-Coupling of (Cyclo)alkenyl/Aryl Bromides and Secondary Phosphine Oxides with in situ Halogen Exchange
An efficient protocol for concurrent tandem halogen exchange/C?P cross-coupling of cycloalkenyl bromides and secondary phosphine oxides has been developed. The catalytic system is based on cheap and air-stable copper(I) iodide as the precatalyst, commercially available N,N’-dimethylethylenediamine as the ligand, and Cs2CO3 or K2CO3 as the base. The use of sodium iodide as an additive reduces the excessive use of organic bromides to near-stoichiometric by promoting the in situ transformation to the corresponding iodides. Diarylphosphine oxides undergo cycloalkenylation with 35–99 % yields and dicyclohexylphosphine oxide with 30–53 % yields. In the case of acyclic alkenyl bromides the cross-coupling products undergo conjugate addition of diphenylphosphine oxide and satisfying yields are observed only for internal olefins. In the case of aryl bromides satisfying yields (43–72 %) are observed only for sterically unhindered arenes or arenes possessing an ortho-directing group. Cycloalkenylphosphine oxides prepared in the cross-coupling reaction undergo base-catalyzed and base-promoted conjugate addition to give bis(phosphinoyl)cycloalkanes.
Stankevi?, Marek,Wo?nicki, Pawe?
supporting information
p. 3484 - 3491
(2021/07/22)

Preparation of cyclopentyl (f) ene-1-boronic acid frequency that ester method
The invention discloses a method of preparing cyclopenten/cyclohexen-1-yl-boronic acid pinacol ester from methyl 1-cyclopentene/cyclohexene-1-carboxylate by three-step continuous operations. The method includes subjecting the raw material to alkaline hydrolysis to form the corresponding 1-alkylene carboxylic acid; performing addition with bromine; performing elimination and decarboxylation at the same time under the existence of DBU or DMAP to produce 1-bromo cyclopentene/cyclohexene; and allowing the 1-bromo cyclopentene/cyclohexene and methoxyboronic acid pinacol ester to form an ester under the existence of magnesium metal by a one-pot process to obtain the cyclopenten/cyclohexen-1-yl-boronic acid pinacol ester. The method is high in continuity, simple and convenient in operations, free of low-temperature reactions, and capable of obtaining the 1-bromo cyclopentene/cyclohexene intermediate with high purity and meeting market demands. The method adopts one-pot-process of Grignard reaction/esterification, so that the method is more convenient in operations and has less by-products, and the product is easier in rectification purification.
-
Paragraph 0019

(2016/10/31)

Formation of enehydrazine intermediates through coupling of phenylhydrazines with vinyl halides: Entry into the Fischer indole synthesis
Cut to the chase: Direct formation of an enehydrazine, an intermediate in the classic Fischer indole synthesis, solves the regioselectivity problem associated with indolization. This approach not only achieves selective synthesis of indoles through proper selection of the vinyl halide, but also leads to quick construction of desoxyeseroline and esermethole, as well as the key structural motif in the Akuammiline alkaloid vincorine. Copyright
Zhan, Fuxu,Liang, Guangxin
supporting information
p. 1266 - 1269
(2013/03/13)

Gold-catalysed alkenyl- and arylsilylation reactions forming 1-silaindenes
In the presence of gold(i)-phosphine catalysts, alkenyl- and arylsilanes undergo intramolecular cyclisation reactions onto appendant alkyne moieties to afford 1-silaindene derivatives. The reaction pathways vary depending on the substituent on silicon. The Royal Society of Chemistry 2011.
Matsuda, Takanori,Yamaguchi, Yoshiyuki,Shigeno, Masanori,Sato, Shinya,Murakami, Masahiro
supporting information; experimental part
p. 8697 - 8699
(2011/09/15)

Ruthenium-catalyzed transformation of alkenyl triflates to alkenyl halides
In the presence of a ruthenium catalyst, alkenyl triflates were found to be transformed to the corresponding bromides, chlorides and iodides simply by treatment with a lithium halide (1.2 equiv.). The Royal Society of Chemistry 2009.
Shirakawa, Eiji,Imazaki, Yusuke,Hayashi, Tamio
supporting information; experimental part
p. 5088 - 5090
(2009/12/08)

Michael addition-elimination mechanism for nucleophilic substitution reaction of cycloalkenyl iodonium salts and selectivity of 1,2-hydrogen shift in cycloalkylidene intermediate
(Chemical Equation Presented) Reactions of cyclohexenyl and cyclopentenyl iodonium salts with cyanide ion in chloroform give cyanide substitution products of allylic and vinylic forms. Deuterium-labeling experiments show that the allylic product is formed via the Michael addition of cyanide to the vinylic iodonium salt, followed by elimination of the iodonio group and 1,2-hydrogen shift in the 2-cyanocycloalkylidene intermediate. The hydrogen shift preferentially occurs from the methylene rather than the methine β-position of the carbene, and the selectivity is rationalized by the DFT calculations. The Michael reaction was also observed in the reaction of cyclopentenyliodonium salt with acetate ion in chloroform. The vinylic substitution products are ascribed to the ligand-coupling (via λ3-iodane) and elimination-addition (via cyclohexyne) pathways.
Fujita, Morifumi,Wan, Hyeok Kim,Fujiwara, Koji,Okuyama, Tadashi
p. 480 - 488
(2007/10/03)

Alkenyl bromides by brominative deoxygenation of ketones in one or two steps
The conversion of ketones into alkenyl bromides is accomplished in one or two steps by 2,2,2-tribromo-2,2-dihydro-1,3,2-benzodioxaphosphole or by the dibromomethyl methyl ether prepared therefrom. Investigations of the scope and limitations provide some hints for the preparative planning and improvement.
Von Roman,Ruhdorfer,Knorr
p. 985 - 992
(2007/10/02)

Halogenative Deoxygenation of Ketones; Vinyl Bromides and/or gem-Dibromides by Cleavage of 1,3-Benzodioxoles (Ketone Phenylene Acetals) with Boron Tribromide
Representative ketones 1 have been converted in generally good yields to the respective 1,3-benzodioxoles 5 by trans-acetalization of ketone dimethyl acetals with 1,2-dihydroxybenzene, and cleaved with boron tribromide. 1,3-Benzodioxoles derived from α-unbranched aliphatic ketones gave in general a mixture of vinyl bromides and gem-dibromides; pure gem-dibromides could be selectively obtained in most of cases using a suitable reaction time. 1,3-Benzodioxoles derived from α-branched ketones gave complex mixtures and their cleavage appears to be of little synthetic signifance. 1,3-Benzodioxoles of aromatic ketones gave vinyl bromides only.Aliphatic cyclic gem-dibromides 3 were converted to the respective vinyl bromides 2 by phase-transfer-catalysed dehydrobromination.
Napolitano, Elio,Fiaschi, Rita,Mastrorilli, Ettore
p. 122 - 125
(2007/10/02)

COMPARISON OF SYN DEHYDROHALOGENATIONS FROM TANS-1-BROMO-2-CHLOROCYCLOALKENES PROMOTED BY COMPLEX BASE AND BY POTASSIUM TERT-BUTOXIDE
Compared with t-BuOK-t-BuOH, syn eliminations from trans-1-bromo-2-chlorocycloalkanes (C4-C8) induced by NaNH2-NaO-t-Bu in THF are rapid, exhibit greater propensity for dehydrochlorination and show little sensitivity to ring size of the dihalocycloalkane.
Croft, Alan P.,Bartsch, Richard A.
p. 2737 - 2740
(2007/10/02)