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3- benzocyclobutene

Simple cyclobutanes do not readily undergo such reactions, but cyclobutenes do. Ben-zocyclobutene derivatives tend to open to give extremely reactive dienes, namely ortho-c]uin(xlimethanes (examples of syntheses see on p. 280, 281, and 297). Benzocyclobutenes and related compounds are obtained by high-temperature elimination reactions of bicyclic benzene derivatives such as 3-isochromanone (C.W. Spangler, 1973, 1976, 1977), or more conveniently in the laboratory, by Diels-Alder reactions (R.P. Thummel, 1974) or by cycliza-tions of silylated acetylenes with 1,5-hexadiynes in the presence of (cyclopentadienyl)dicarbo-nylcobalt (W.G, Aalbersberg, 1975 R.P. Thummel, 1980). [Pg.80]

Two approaches to convergent steroid syntheses are based on the thermal opening of benzocyclobutenes to the o-quinodimethane derivatives (see p. 80 W. Oppolzer, 1978 A) and their stereoselective intramolecular Diels-Alder cyclizations. T, Kametani (1977 B, 1978) obtained (+ )-estradiol in a six-step synthesis. The final Diels-Alder reaction occurred regio- and stereoselectively in almost quantitative yield, presumably because the exo transition state given below is highly favored over the endo state in which rings A and D would stcrically inter-... [Pg.280]

A similar synthesis starts from commercially available 1,5-hexadiyne and 2-methyl-cyclopent-2-enone. The benzocyclobutene is obtained from a bis-acetylene in a cobalt-catalyzed reaction. It rearranges regio- and stereoselectively to a 3-deoxy steroid derivative. The overall yield from the cyclopentenone was 40% (R.L. Funk, 1977). [Pg.281]

The Diels-Alder reaction of o-quinodimethanes (from benzocyclobutenes) with nitrogen-ubstituted enes has also been applied to alkaloids synthesis (see p. 280f. T. Kametani, 1972, 1973, 1974 W. Oppolzer, 1978 A). [Pg.297]

The benzocyclobutene ring stmcture is a latent reactive diene because it tautomerizes to o-xylylene on heating according to the foUowiag ... [Pg.403]

The diene undergoes Diels-Alder cycloaddition with dienophiles. Polyimides have been synthesized from various imide-containing benzocyclobutenes and dienophiles (83—85). [Pg.403]

A number of dielectric films are deposited by the spin-on technique. In this case the film s constituent molecules are dissolved in a solvent to form a hquid. After spinning the Hquid over a semiconductor surface the solvent is driven off with a baking step, leaving behind the thin dielectric film. Common films include polyimide and benzocyclobutene (BCB). The deposition process for these films is simple, making it attractive for a manufacturing process. [Pg.384]

As exemplified in the present procedure, the reaction has been optimized and extended in scope it affords functionalized benzocyclobutenes as well as substituted isoquinolines in high yields. Benzocyclobutenes have been used as intermediates in the synthesis of many naturally occurring alkaloids, - steroids,polycyclic terpenoids,and anthracycline antibiotics. The traditional routes leading to the preparation of benzocyclobutenes have been... [Pg.80]

Tan et al. investigated polymers made from bis-benzocyclobutenes [13-15]. As the benzocyclobutane is analogous to tbe dien, tbe Diels-Alder addition takes place. This reaction is applied to the preparation of polyimides. The advantage of this system is that the resultant polymer is oxidized to form thermally stable aromatic polyimides (Fig. 7). [Pg.816]

UV irradiation of hexafluorobenzene with indene or cycloalkenes gives high yields of 2+2 adducts, which undergo further intramolecular cycloaddition to form hexafluoropolycycloalkanes [754] (equation 38) Photolysis of fluormated deriva tives of vinylbenzenes afford benzocyclobutenes, whereas allyl benzenes yield Dewar benzene-type products [755]... [Pg.926]

The reaction of an alicyclic enamine with benzyne intermediate yields simple arylation products and/or 1,2-cycloaddition products, depending upon the reaction conditions 102). This is illustrated by the reaction of l-(N-pyrrolidino)cyclohexene with benzyne (86) (obtained from fluoro-benzene and butyl lithium or o-bromofluorobenzene and lithium amalgam), which produces benzocyclobutene 87 102). [Pg.232]

In the reactions of benzyne with enamines, arylated enamines or amino-benzocyclobutenes can be obtained, depending on reaction conditions and the structure of the enamine. Thus the presence of a proton source such as a secondary amine will favor the enamine product through capture of the zwitterionic intermediate, whereas in the absence of protons one sees... [Pg.381]

Benzocyclobutene-l,2-dione (11) can be condensed with benzene-1.2-diamine to provide an annulated quinoxaline (cf. Houben-Weyl, Vol. E9b/Part 2, p203), which on oxidation with hydrogen peroxide in acetic acid leads to the 1,4-diazocine derivative 12.34... [Pg.535]

With substituted benzocyclobutene-1.2-diones other derivatives are available.36 Radical intermediates seem to be involved in the reaction process.37... [Pg.535]

Bei der Reduktion von 1,2-Dibrom-benzocyclobuten wird als einziges Dimerisations-produkt 6a,lOb-Dihydro-(benzo-[a]-biphenylen) isoliert5 ... [Pg.667]

Shishido, K., Shitara, E., Komatsu, H., Hiroya, K., Fukumoto, K., Kametani, T. (1986) Total Syntheses of ( )-Physovenine and ( )-Physostigmine. An Application of Tandem ElectrocycUc-[3,3]Sigmatropic Reaction of Benzocyclobutenes. Journal of Organic Chemistry, 51, 3007-3011. [Pg.197]

This reaction can be applied to substituted benzocyclobutenes. For example, the reaction has been used to form an array of five linear rings containing most of the functionality for the antibiotic tetracycline. [Pg.489]

Benzocyclobutene, Butyllithium, Potassium fert-butoxide Adcock, W. et al., J. Organomet. Chem., 1975, 91, C20... [Pg.1338]

For the synthesis of estradiol methyl ether 4-319, the cydobutene derivative 4-317 was heated to give the orthoquinonedimethane 4-318 which cydized in an intramolecular Diels-Alder reaction [109]. The thermally permitted, conrotatory elec-trocyclic ring-opening of benzocyclobutenes [110] with subsequent intramolecular cycloaddition also allowed the formation of numerous complex frameworks (Scheme 4.70). [Pg.326]

Malacria and coworkers [274] used an intermolecular trimerization of alkynes to gain efficient access to the skeleton of the phyllocladane family. Thus, the Co-cata-lyzed reaction of the polyunsaturated precursor 6/4-4 gave 6/4-5 in 42% yield. Here, six new carbon-carbon bonds and four stereogenic centers are formed. The first step is formation of the cyclopentane derivative 6/4-6 by a Co-catalyzed Conia-ene-type reaction [275] which, on addition o f his( Iri me ill y I si ly 1) e thy ne (btmse), led to the benzocyclobutenes 6/4-7 (Scheme 6/4.2). The reaction is terminated by the addition of dppe and heating to reflux in decane to give the desired products 6/4-5 by an electrocyclic ring opening, followed by [4+2] cycloaddition. [Pg.458]


See other pages where 3- benzocyclobutene is mentioned: [Pg.99]    [Pg.297]    [Pg.403]    [Pg.29]    [Pg.29]    [Pg.277]    [Pg.680]    [Pg.81]    [Pg.535]    [Pg.382]    [Pg.214]    [Pg.155]    [Pg.158]    [Pg.158]    [Pg.159]    [Pg.160]    [Pg.164]    [Pg.790]    [Pg.535]    [Pg.670]    [Pg.317]    [Pg.326]    [Pg.18]    [Pg.1098]    [Pg.496]    [Pg.211]    [Pg.955]    [Pg.1339]    [Pg.328]   
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1.5- Hexadiynes benzocyclobutene synthesis

4-Bromo-benzocyclobutene

AB Benzocyclobutene Monomers and Polymers

AB maleimide benzocyclobutene

Alkynes benzocyclobutenes

Anthracene benzocyclobuten

Anthracyclines via benzocyclobutene ring opening

Anthraquinones via benzocyclobutene ring opening

Benzocyclobutene -containing

Benzocyclobutene Derivatives as Intermediates

Benzocyclobutene Diels-Alder reaction with

Benzocyclobutene alkene

Benzocyclobutene aryne

Benzocyclobutene derivative

Benzocyclobutene derivative synthesis

Benzocyclobutene dienophiles

Benzocyclobutene electrocyclization

Benzocyclobutene nitrile

Benzocyclobutene polymers

Benzocyclobutene ring

Benzocyclobutene ring closur

Benzocyclobutene synthesis

Benzocyclobutene via arynes

Benzocyclobutene via thermolysis of benzothiophene dioxides

Benzocyclobutene, 1 -methoxy-1 -phenylrearrangement

Benzocyclobutene, 1 -methoxy-1 -phenylrearrangement anthracene synthesis

Benzocyclobutene, 3-methyl

Benzocyclobutene, 3-methyl synthesis

Benzocyclobutene, 3-methyl via benzynes

Benzocyclobutene, 7,8-diphenyl

Benzocyclobutene, cycloaddition reactions

Benzocyclobutene, cycloaddition reactions fulvenes

Benzocyclobutene, diphenylone-electron transfer

Benzocyclobutene, ring expansion

Benzocyclobutene-1,2-dione

Benzocyclobutene-1,2-dione, 3-hydroxy-5-methylsynthesis

Benzocyclobutene-1,2-dione, 3-hydroxy-5-methylsynthesis via cycloaddition

Benzocyclobutene-1,2-diones

Benzocyclobutene-Acetylene Polymers

Benzocyclobutene-Maleimide Polymers

Benzocyclobutenes

Benzocyclobutenes 3- substituted

Benzocyclobutenes Benzocyclobutenols

Benzocyclobutenes Diels-Alder reactions

Benzocyclobutenes cycloaddition reactions

Benzocyclobutenes electrocyclic ring opening

Benzocyclobutenes formation

Benzocyclobutenes fulvenes

Benzocyclobutenes isochroman-3-ones

Benzocyclobutenes o-quinodimethane precursors

Benzocyclobutenes rearrangement

Benzocyclobutenes synthesis

Benzocyclobutenes thermolysis

Benzocyclobutenes via cycloadditions

Benzocyclobutenes, 1-substituted, from

Benzocyclobutenes, pyrolysis

Benzopyrans, dihydrosynthesis via benzocyclobutenes

Benzothiophene 2,2-dioxides, 2,5-dihydrothermolysis benzocyclobutene synthesis

Bicyclo octa-l,3,5-trienes s. Benzocyclobutenes

Bicyclo octanes benzocyclobutene synthesis

By Thermolysis of Benzocyclobutenes

Diterpene alkaloids via benzocyclobutene ring opening

Electrocyclic reactions benzocyclobutene

Estradiol via benzocyclobutene ring opening

Estrone via benzocyclobutene ring opening

Fulvene, 6,6-dimethylcycloaddition reactions benzocyclobutenes

Imide benzocyclobutene

Isochroman-3-one via benzocyclobutene ring opening

Morphinans via benzocyclobutene ring opening

Norsteroids via benzocyclobutene ring opening

O-Quinodimethanes via benzocyclobutenes

Poly(Benzocyclobutenes)

Quinolines, dihydrosynthesis via benzocyclobutenes

Radical ring-opening benzocyclobutene

Substitution 3- substituted benzocyclobutenes

Thermolysis of benzocyclobutenes

Triterpenes via benzocyclobutene ring opening

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