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Topic: Dienophile

	[No title]
		Cyclopentadiene is the diene (end Cs of the diene component are blue) and ethyne is the dienophile (Cs of the dienophile component are green).
		The end Cs of the diene component are blue, the Cs of the dienophile double bond are green, and the O is red.
		The end Cs of the diene component are blue, the Cs of the dienophile double bond are green, the N is gold, and the Os are red.
	www.du.edu /~jhornbac/organic/prob20-14.html (313 words)

	Diels-Alder Reaction (Site not responding. Last check: 2007-11-06)
		There are various approaches used to determine the identity of the diene and dienophile, all of which involve disconnecting the six-membered ring in question into suitable pieces to determine what two molecules (i.e.
		Remember that in the starting materials there were double bonds between carbons 1 and 2 and between carbons 3 and 4 of the conjugated diene, and a(nother) π-bond between the two carbons of the dienophile.
		The mechanism of the Diels-Alder reaction is usually shown using a cyclic flow of electrons between the diene and the dienophile.
	www.rocky.edu /~barbaroj/diels-alder/diels-alder.html (477 words)

	Experiment 8 Background (Site not responding. Last check: 2007-11-06)
		Dienophiles with symmetric LUMOs are not expected to react regioselectively with isoprene.
		Dienophile substituents interact with the adjacent CC double bond, and these interactions warp the shape of the CC antibond orbital.
		According to FMO theory, the tendency of a dienophile to react regioselectively is inversely correlated with its LUMO symmetry.
	academic.reed.edu /chemistry/alan/201_202/lab_manual/Experiment_8/background.html (2478 words)

	Diels-Alder Reaction Stereochemistry
		Let's remember that, since the Diels-Alder reaction is a concerted reaction, the stereochemical relationships between the subsituents on the diene (relative to one another) and on the dienophile remain constant.
		Unlike the substituents all on the diene or all on the dienophile, the relationship here depends on the orientation of the groups when the successful collision occurs.
		When the dienophile is substituted with electron-withdrawing groups, and when the diene is substituted with electron-donating substituents, as is usually the case, the reaction is actually quite predictable.
	academics.keene.edu /rblatchly/OrgoCommon/hand/conjdiene/DARxnStereochem.html (564 words)

	Method for preparing 1.alpha.-hydroxyvitamin D compounds - Patent 4554106
		The diazo-p-benzoquinone or diazonaphthoquinone dienophiles, although also useful for purposes of the present invention, because of their extremely high reactivity require conducting the reaction at exceedingly low temperatures to achieve discrimination in adduct formation between cis and trans vitamin D compounds, offer less advantage.
		For highly reactive dienophiles, temperatures in the lower part of the range indicated are appropriate, for the less reactive ones the upper temperature range is preferred.
		Obviously, unduly prolonged reaction of a cis/trans vitamin D mixture with a dienophile is to be avoided to prevent losses of the desired 5,6-cis-vitamin D compound owing to its reaction (adduct formation) with the dienophile.
	www.freepatentsonline.com /4554106.html (2783 words)

	Furo[3,4-b]indoles and thieno[2,3-c]furans via a Pummerer induced cyclization reaction
		In the absence of a dienophile it was possible to isolate 4-ethylthio-6-phenyl-thieno[2,3-c]furan and 1-ethylthio-4-phenylsulfonyl-4H-furoindole.
		However, when the reaction was carried out in the absence of a dienophile, we were able to isolate thieno[2,3-c]furan 18 in 79% yield.
		When the reaction was carried out in the absence of a dienophile, it was possible to isolate furo[3,4-b]indole 29 in 78% yield.
	www.ch.ic.ac.uk /ectoc/echet96/papers/016 (2410 words)

	Diels-Alder Reaction
		The [4+2]-cycloaddition of a conjugated diene and a dienophile (an alkene or alkyne), an electrocyclic reaction that involves the 4 π-electrons of the diene and 2 π-electrons of the dienophile.
		In addition, either the diene or the dienophile can be substituted with cumulated double bonds, such as substituted allenes.
		The Diels-Alder reaction is favored by electron-withdrawing groups on the dienophile and by electron-donating groups on the diene, or vice-versa (inverse electron demand, inverse Diels-Alder reaction).
	www.organic-chemistry.org /namedreactions/diels-alder-reaction.shtm (223 words)

	Catalysts patent (Site not responding. Last check: 2007-11-06)
		A process for performing a catalytic Diels-Alder reaction by reacting a diene with a dienophile in the presence of a heterogeneous catalyst comprising a zeolitic material exchanged or impregnated with ions of a Lewis acidic metal is described.
		In formal Diels-Alder reactions the dienophile is a compound containing a carbon-carbon double or triple bond, for example a vinyl or acetylenic compound, and the diene possesses two carbon-carbon double bonds, separated by a carbon-carbon single bond.
		A disadvantage with auxiliaries however is that they can alter the electronic properties of the diene or dienophile with the consequence that the reaction may become more difficult to control and predict in terms of rate, enantioselectivity and, where the diene is a cyclic compound such as cyclopentadiene, the endo:exo ratio.
	www.freshpatents.com /Catalysts-dt20050210ptan20050033100.php (2723 words)

	[No title] (Site not responding. Last check: 2007-11-06)
		The pesticide Aldrin is prepared by a Diels-Alder reaction between hexachlorocyclopentadiene (the diene) and norbornadiene (the dienophile).
		This compound was then reacted as the dienophile with cyclopentadiene as the diene.
		Chlordane is prepared by a Diels-Alder reaction between hexachlorocyclopentadiene (diene) with cyclopentadiene (dienophile).
	www.du.edu /~jhornbac/organic/pesticides.html (150 words)

	Organic Chemistry, Bruice Chapter 7 -- Practice Exercise 2 (Site not responding. Last check: 2007-11-06)
		The diene has 4 atoms and the dienophile has 2 atoms.
		The diene has 2 pi electrons and the dienophile has 4 pi electrons.
		The diene has 4 neutrons and the dienophile has 2 neutrons.
	cwx.prenhall.com /bookbind/pubbooks/bruice/chapter7/multiple2/deluxe-content.html (364 words)

	World Intellectual Property Organization (Site not responding. Last check: 2007-11-06)
		The dienophile can be any group, including but not limited to, a substituted or unsubstituted alkene, or a substituted or unsubstituted alcyne.
		The high selectivity of a diene or dienophile for reaction with the corresponding dienophile or diene, respectively, eliminates the need to protect functional groups during the synthesis of biomolecules, such as oligonucleotides or peptides.
		Additionally, the diene and dienophiles are not susceptible to the side-reactions typically encountered in known immobilization methods.
	www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/84234.011108&ELEMENT_SET=DECL (7074 words)

	Projection Experiment: (4+2)-Cycloadditions (Diels-Alder)
		In a Diels-Alder cycloaddition a unsaturated compound (dienophile) is added in 1,4-position to a compound which has two conjugated double bonds (diene).
		The Diels-Alder reaction is stereospecific with respect to both the diene and the dienophile.
		The different reaction rates permit a valuation of the dienophile and of the diene: N-NPT is a better Diels-Alder dienophile than p-benzoquinone.
	www.uni-regensburg.de /Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/p2_cyclo_add-e.htm (506 words)

	Diels-Alder reaction (Organic chemistry) - Wikibooks
		In the Diels-Alder reaction, a conjugated diene reacts with a dienophile.
		The dienophile is named for its affinity to react with the diene.
		Because dienes and dienophiles are often gasses, this reaction usually takes place in a sealed container at elevated pressure and temperature.
	en.wikibooks.org /wiki/Diels-Alder_reaction_(Organic_chemistry) (243 words)

	Phenolic-modified rosin ester printing inks - Patent 4857624
		A method in accordance with claim 1 wherein the dienophile is selected from the group consisting of fumaric acid, maleic acid, maleic anhydride, acrylic acid, methacrylic acid and itaconic acid.
		The preferred dienophiles for reaction with the rosin component are fumaric acid, maleic acid, acrylic acid, methacrylic acid, itaconic acid and maleic anhydride.
		The dienophile is preferably used in an amount of from about 0.16 to about 1.0 equivalents per equivalent of rosin and more preferably comprises from about 0.3 to about 0.6 equivalents per equivalent of rosin.
	www.freepatentsonline.com /4857624.html (6399 words)

	Chemistry 2302
		A Diels-Alder reaction involves cycloaddition between a diene and a dienophile.
		On the other hand, the dienophile has a p bond, and is more reactive when electron-withdrawing substituents are present.
		The first involves the reaction between furan as a diene and 4-phenyl-1,2,4-triazolin-3,4-dione (N-PTD) as the dienophile.
	vesta.chem.umn.edu /classes/ch2302s02/demos/demo2.htm (255 words)

	Vinylboranes as trans-Dihydroxyethylene Equivalents for Diels-Alder Reactions
		We report here a conceptually new method for catalysis of Diels-Alder reactions in which an electron-withdrawing activating group is temporarily covalently bound to the dienophile during the catalytic cycle.
		The dienophile 2 was of interest as an acetylene equivalent due to a facile elimination from the assumed intermediate 4 to form 3.
		Since 5 is now an activated dienophile, it can react with the diene to form 7, which could then eliminate the haloborane to afford the product 3 and continue the catalytic cycle.
	www.chem.tamu.edu /rgroup/singleton/catcov.html (823 words)

	[No title] (Site not responding. Last check: 2007-11-06)
		The Diels-Alder Reaction is an organic chemical reaction between a conjugated diene and a substituted alkene (commonly termed the dienophile) to form a substituted cyclohexene system.
		The reaction can proceed even if some of the atoms in the newly-formed ring are not carbon.
		Otto Paul Hermann Diels and Kurt Alder were awarded the Nobel Prize in Chemistry in 1950 for their work on this reaction.
	www.informationgenius.com /encyclopedia/d/di/diels_alder_reaction.html (173 words)

	[No title]
		The Diels-Alder reaction is an example of a cycloaddition reaction between two molecular components: the diene and the dienophile.
		Therefore, a total of 6 pi electrons are involved in the reaction mechanism --- 4 pi electrons from the diene and 2 pi electrons from the dienophile.
		Calculate the amount of maleic anhydride required to react with the diene based upon the fact that the diene and dienophile react in a 1:1 equivalency ratio.
	www.naz.edu:9000 /~organic/spring/laboratory/spexp3.htm (734 words)

	Lecture 23 - Diels-Alder Reaction (Site not responding. Last check: 2007-11-06)
		The reaction basics: a combination of a conjugated diene and an alkene or alkyne (termed the dienophile).
		The take-home lesson is that the result of this energy requirement is that electron rich dienes react well with electron poor dienophiles and electron poor dienes react well with electron rich dienophiles.
		The more compact is call the endo form, with the diene and the dienophile stacked on top of each other.
	chemiris.chem.binghamton.edu /HANDY/chem231/lect2223/lect23.htm (365 words)

	ATN Scientific Computing - Application: Spartan (Site not responding. Last check: 2007-11-06)
		Acrolein is known to be a Diels-Alder dienophile.
		The BF adduct of acrolein is even a better Diels-Aler dienophile than acrolein itself.
		The usual explanation is that the complexation reduces the energy of the lowest-unoccupied molecular orbital (LUMO) on the dienophile.
	www.unc.edu /atn/asg/applications/spartan/acrolein-bf3.html (547 words)

	0130a10
		In all these cases, the dienophile double or triple bond is next to the positively
		sterechemistry of the starting dienophile is maintained during the reaction.
		cases, trans diene are converted to cis diene, then react with dienophile.
	www.chem.latech.edu /~hji/course251/10jan29/0130a10.html (426 words)

	Studying Perturbation theory with Explorer EyeChem and VRML
		In studying the properties of one moiety being perturbed by the other in the Diels-Alder reaction, one approach would be the calculation of the Molecular Orbitals (MO) for each moiety (dieno and dienophile) instead of the MO of the supermolecule (dieno plus dienophile).
		In this case we are considering the dimerization of 2-cyano-butadiene, with the double bond (C1-C2) of one moiety as a dienophile.
		As in the previous reaction, we consider the dimerization of 2-methoxy-butadiene, with the para adduct being the observed one.
	www.ch.ic.ac.uk /ectoc/papers/70 (1339 words)

	[No title]
		In this project, I studied how properties of the dienophile affect the rate of reaction, as well as studying transition states, kinetic and thermodynamic reaction pathways, and stereoselectivity in one example of Diels-Alder.
		For part one, diene and dienophile geometries were optimized, and HOMO and LUMO energies, respectively, were calculated at the ab initio 3-21G level.
		In the electrostatic potential map of the diene, the region that, according to the accepted mechanism, is brought near the dienophile has distinct electronegative regions.
	www.shodor.org /succeed/compchem/projects/fall00/dielsalder/outlinee.htm (1036 words)

	(Z)-3-p-Tolylsulfinylacrylonitrile as a Chiral Dienophile: Diels-Alder Reactions with Furan and Acyclic Dienes (Site not responding. Last check: 2007-11-06)
		(Z)-3-p-Tolylsulfinylacrylonitrile as a Chiral Dienophile: Diels-Alder Reactions with Furan and Acyclic Dienes
		-facial selectivity, which is almost complete in all cases, the approach of the diene from the less-hindered face of the dienophile (that bearing the lone electron pair) in the predominant rotamer being the favored one.
		Additionally, the reactivity of compound 1 as well as its endo-selectivity are both higher than those observed for the corresponding (Z)-3-sulfinylacrylates, thus proving the potential of sulfinylnitriles as chiral dienophiles.
	pubs.acs.org /cgi-bin/jtext?joceah/65/i23/abs/jo000963g (179 words)

	Diels Alder Reaction - EMOC (Site not responding. Last check: 2007-11-06)
		The Diels Alder reaction is a unique reaction of dienes with either alkenes or alkynes, which are referred to as dienophiles.
		Stereoselectivity is observed for the Diels Alder reaction.
		This overlap is achieved when the planes of the diene and dienophile are oriented parallel and on top of each other.
	www.chem.memphis.edu /parrill/EMOC/roadmap/da.html (231 words)

	Diels-Alder Mechanism
		Since this reaction forms two new carbon-carbon bonds in a single step, it is a very useful and powerful reaction (one which earned Otto Diels and Kurt Alder a Nobel prize in chemistry for discovering it).
		If your dienophile is disubstituted (substituted twice), there is the possibility for stereochemistry in the product.
		Since the dienophile is cis disubstituted, you get the endo stereochemistry with the two cyano (CN) substituents pointing away from the top of the bicyclo compound.
	www.chemhelper.com /dielsalder.html (520 words)

	An efficient total synthesis of the pyrroquinazolinoquinoline alkaloid Luotonin A, employing an intramolecular hetero ... (Site not responding. Last check: 2007-11-06)
		The intramolecular hetero- Diels–Alder reaction of an aryl imino ether (diene) with an aryl nitrile (dienophile) has been used as the key reaction in an efficient approach to the pyrroquinazolino-quinoline alkaloid, luotonin A. Activation of the diene moiety by the incorporation of a methoxy group played an important role for the hetero Diels–Alder reaction.
		We have been especially interested in the reactivity of the acetylene moiety (as a dienophile) in thermal Diels–Alder reactions.
		After installation of the dienophile part, the amide 10 was subjected to intramolecular hetero Diels–Alder reaction.
	www.arkat-usa.org /ark/journal/2003/I08_Fukumoto/KF-662H/KF-662H.asp (1883 words)

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