5-Bromo-1-pentene

C5H9Br 2-bromo-1-pentene 31844-95-8 381.15 33.538 1,2 5047 C5H9CI 4-chloro-3-methyl-1 -butene 10524-01-3 365.15 31.098 1,2... 

In a typical example of the malonic ester synthesis 6 heptenoic acid has been pre pared from 5 bromo 1 pentene... 

H2C=CHCH2CH2CH2Br + CH2(COOCH2CH3)2 5 Bromo 1 pentene Diethyl malonate... 

When 2-bromo-2-methylpentane is dissolved in DMF, the formation of 2-methyl-1-pentene (A) and 2-methyl-2-pentene (B) occurs. The ratio of alkenes formed is not... 

Treatment of 4-penten-l-ol with aqueous Br2 yields a cyclic bromo ether rather than the expected bromohydiin. Suggest a mechanism, using curved arrows to show electron movement. 

A chemist requires a large amount of l-bromo-2-pentene as starting material for a synthesis and decides to carry out an NBS allylic broinination reaction. What is wrong with the following synthesis plan What side products would form in addition to the desired product ... 

LS,4.S )-(E)-2-Bromo-4-l(2-methoxyethoxy)methoxy]-l-phenyl-2-penten-l-ol (3 A, R = C6H5 R2 = II) Typical Procedure49 ... 

It has been shown that halogen-substituted alkenes can participate in the metathesis reaction, e.g. 5-bromo-l-pentene reacts with 2-pentene 11). A very interesting reaction is the conversion of methyl-9-octa-decenoate into 9-octadecene and dimethyl-9-octadecenedioate 12) ... 

Pentanal, 5-amino [14049-15-1], 121 Pentane, 1-bromo- [110-53-2], 82 Pentanediotc acid [ 110-94-1 ], 98 3-Pentenoicacid, 4-methyl- [504-85-8], 70 3-Penten-2-ol, 3-bromo-, acetate [14362-79-9], 35... 

Pentenoic acid 4-methyl-, 70 3 Penten 2-ol, 3 bromo, acetate, 35 3-Penten-2-ol, 3-bromo-4-methyl-, acetate,... 

This procedure illustrates a general method for the stereoselective synthesis of ( P)-disubstitnted alkenyl alcohols. The reductive elimination of cyclic /3-halo-ethers with metals was first introduced by Paul3 and one example, the conversion of tetrahydrofurfuryl chloride [2-(chloromethyl)tetrahydrofuran] to 4-penten-l-ol, is described in an earlier volume of this series.4 In 1947 Paul and Riobe5 prepared 4-nonen-l-ol by this method, and the general method has subsequently been applied to obtain alkenyl alcohols with other substitution patterns.2,6-8 (I )-4-Hexen-l-ol has been prepared by this method9 and in lower yield by an analogous reaction with 3-bromo-2-methyltetra-hydropyran.10... 

Synthesis of Functionalized Enynes by Palladium/Copper-catalyzed Coupling Reactions of Acetylenes with (Z)-2,3-Dibromopropenoic Acid Ethyl Ester (Z)-2-Bromo-5-(trimethylsilyl)-2-penten-4-ynoic Acid Ethyl Ester. 

Addition of halocarbons to alkenes in the presence of transition metals is a well-known radical reaction. Weinreb etal. have now reported an intramolecular version leading to cyclic esters or bicyclic lactones. Typical substrates are the a,a-dichloro ester 1 or the a,a-dichloro acid 2, readily available by reaction of ethyl lithiodi-chloroacetate with 5-bromo-l-pentene. When 1 is heated in benzene at 160° with a metal catalyst, mixtures of epimeric ot,w-dichloro esters 3 and 4 are obtained. The ratio and yields of 3 and 4 are dependent on the catalyst and concentration of 1, but 3 and 4 are the major products formed in the presence of Ru(II) and Fe(II) catalysts. In contrast cyclization of 2 under the same conditions gives the bicyclic y-lactone 5 in high yield. 

SYNTHESIS OF FUNCTIONALIZED ENYNES BY PALLADIUM/COPPER-CATALYZED COUPLING REACTIONS OF ACETYLENES WITH (Z)-2,3-DIBROMOPROPENOIC ACID ETHYL ESTER (Z)-2-BROMO-5-(TRIMETHYLSILYL)-2-PENTEN-4-YNOIC... 

Penten-4-ynoic acid, 2-bromo-S-(trlmethylsilyl)-, ethyl ester, (Z)-)... 

C, pot temperature 125°C) prior to collection of the product. (Z)-2-Bromo-5-(trimethylsilyl)-2-penten-4-ynoic acid ethyl ester is collected (bp 105-108°C, 0.9 mm, pot temperature < 125°C) as a pale yellow oil (10.95-12.85 g, 48-56%) and is shown by capillary GC to be 87-94% pure (contaminants include bis(trimethylsilyl)butadiyne, < 2% and (E)-2-[(trimethylsilyl)ethynyl]-5-(trimethylsilyl)-2-penten-4-ynoic acid ethyl ester, 6-11% Notes 11-13). 

Ethyl (Z)-2-bromo-5-(trimethylsilyl)-2-penten-4-ynoate 2-Penten-4-ynoic acid, 2-bromo-5-(trimethylsilyl)-, ethyl ester, (Z)- (12), (124044-21-9)... 

S)-(-)-CITRONELLOL from geraniol. An asymmetrically catalyzed Diels-Alder reaction is used to prepare (1 R)-1,3,4-TRIMETHYL-3-C YCLOHEXENE-1 -CARBOXALDEHYDE with an (acyloxy)borane complex derived from L-(+)-tartaric acid as the catalyst. A high-yield procedure for the rearrangement of epoxides to carbonyl compounds catalyzed by METHYLALUMINUM BIS(4-BROMO-2,6-DI-tert-BUTYLPHENOXIDE) is demonstrated with a preparation of DIPHENYL-ACETALDEHYDE from stilbene oxide. A palladium/copper catalyst system is used to prepare (Z)-2-BROMO-5-(TRIMETHYLSILYL)-2-PENTEN-4-YNOIC ACID ETHYL ESTER. The coupling of vinyl and aryl halides with acetylenes is a powerful carbon-carbon bond-forming reaction, particularly valuable for the construction of such enyne systems. 

In a series of studies, substituents were introduced or varied at the 2-positions of the thiophene rings of di(benzothienyl)ethenes. The reactions of 3-bromo-2(n-aIkyl)-l-benzothiophene with BuLi and octafluorocyclo-pentene gave bis(2-n-alkyl-l -benzothiophen-3-yl)perfluorocyclo-pentenes 60 containing alkyl substituents with a different chain length at position 2 of the benzothiophene ring. The authors stated that the Et-, Pr-, and Bu-containing derivatives exhibit photochromic properties even in the crystalline state (06JPP(A)162). 

The Pirrung synthesis is notable for its brevity and clever amalgamation of [2 + 2] photocycloaddition and Wagner-Meerwein rearrangement chemistry Enol ether 757 was reacted with the Grignard rea nt from 5-bromo-2-methyl-l-pentene, subjected to acid hydrolysis, and irradiated to generate the tricycle 738. Wittig olefination of this ketone and treatment with p-toluenesulfonic acid provided racemic isocomene. 

Problem 6.1 Write structural formulas for (a) 3-bromo-2-pentene, (b) 2,4-dimethyl-3-hexene, (c) 2,4,4-trimethyl-2-pentene, (d) 3-ethylcyclohexene. 

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