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Topic: Diels Alder cycloaddition reaction

	Diels-Alder reaction - Wikipedia, the free encyclopedia
		The Diels-Alder reaction is an organic chemical reaction (specifically, a cycloaddition) between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system.
		Otto Paul Hermann Diels and Kurt Alder were awarded the Nobel Prize in Chemistry in 1950 for their work on this reaction.
		The problem is that ketene itself cannot be used in Diels-Alder reactions because it reacts with dienes in unwanted manner (by [2+2] cycloaddition), and therefore "masked functionality" approach has to be used.
	en.wikipedia.org /wiki/Diels-Alder_reaction (2049 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.
		There are “inverse demand” Diels Alder Reactions that involve the overlap of the HOMO of the dienophile with the unoccupied MO of the diene.
		This alternative scenario for the reaction is favored by electron-donating groups on the dienophile and an electron-poor diene.
	www.organic-chemistry.org /namedreactions/diels-alder-reaction.shtm (400 words)

	Modern Valence-Bond Description of Chemical Reaction Mechanisms: Diels-Alder Reaction
		The electronic mechanism for the gas-phase Diels-Alder cycloaddition reaction is studied through a combination of modern valence-bond (VB) theory in its spin-coupled (SC) form and intrinsic reaction coordinate calculations utilizing a complete-active-space self-consistent field (CASSCF) wave function.
		Throughout the reaction, the nonorthogonal SC orbitals resemble well-localized sp
		The visual changes in the SC wave function as the system follows the reaction path strongly suggest that the best schematic representation of the Diels-Alder reaction is through a "homolytic" mechanism, in which six half-arrows indicate the simultaneous breaking of the three
	pubs.acs.org /cgi-bin/abstract.cgi/jacsat/1998/120/i16/abs/ja9741741.html (330 words)

	Orbital Symmetry in Cycloaddition Reactions (Site not responding. Last check: 2007-10-29)
		Cycloaddition reactions are extremely vital in organic syntheis work.
		The Diels-Alder is sometimes called a [4+2] cycloaddition, indicating a hydrocarbon of four carbons combines with one of two carbons.
		The reaction is concerted, meaning all changes in the electron distribution occur simultaneously or in one step.
	user.mc.net /~buckeroo/OSCR.html (200 words)

	Chapter 10: Diels-Alder reaction
		The Diels-Alder reaction is a conjugate addition reaction of a conjugated diene to an alkene (the dienophile) to produce a cyclohexene.
		Due to the high degree of regio- and stereoselectivity (due to the concerted mechanism), the Diels-Alder reaction is a very powerful reaction and is widely used in synthetic organic chemistry.
		The two reactions shown above require harsh reaction conditions, but the normal Diels-Alder reaction is favoured by electron withdrawing groups on the electrophilic dienophile and by electron donating groups on the nucleophilic diene.
	www.chem.ucalgary.ca /courses/351/Carey/Ch10/ch10-5.html (297 words)

	Diels-Alder reaction (Site not responding. Last check: 2007-10-29)
		Diels, O.; Alder, K. Ann., 1928, 460, 98.
		Diels, O.; Alder, K.; Lubbert, W.; Naujokas, E.; Querberitz, F.; Rohl, K.; Segeberg, H. Ann., 1929, 470, 62.
		Diels, O.; Alder, K. Ber., 1929, 62, 2081, 2087.
	orgchem.chem.uconn.edu /namereact/dielsalder.html (66 words)

	Diels-Alder Reaction
		The simplest Diels-Alder Reaction is the reaction of 1,3-butadiene and ethylene to yield cyclohexene (Figure 1).
		The Diels-Alder reaction is a thermal cycloaddition whose mechanism involves the sigma-overlap of the pi-orbitals of the two unsaturated systems.
		To compare Diels-Alder reactions, it is a good approximation to study only the reaction enthalpies (Hess' law (3) enables us to calculate them easily with the outputs of the calculations which are often heats of formation).
	www.ch.ic.ac.uk /motm/porphyrins/introDA.html (1141 words)

	Chemistry 210 Experiments (Site not responding. Last check: 2007-10-29)
		One direct approach, known as the Fischer esterification reaction, involves the acid-catalyzed condensation of an alcohol and a carboxylic acid, yielding an ester and water.
		Exp IX: Diels-Alder Cycloaddition: The Reaction of Cyclopentadiene with Maleic Anhydride
		This reaction forms a six-membered ring from two pieces: a conjugated "diene" (which provides four of the ring atoms) and a "dieneophile" (which provides two of the ring atoms).
	www.miracosta.edu /home/dlr/210exp.htm (1476 words)

	The Diels-Alder Reaction (Site not responding. Last check: 2007-10-29)
		The Diels-Alder reaction is one of the most fascinating organic reactions, both in terms of its synthetic potential and its reaction mechanism.
		From studies of the stereochemistry of the reaction, it is known that it occurs via a suprafacial transition state, which is though to be concerted, i.e.
		One theoretical approach to this reaction which has had a tremendously successful history is to consider it in terms of the Frontier Orbitals involved.
	www.chm.bris.ac.uk /~chjnh/msci_pract/back_da.html (398 words)

	Jiyoung Chang \| Kiessling Lab (Site not responding. Last check: 2007-10-29)
		Her graduate research aimed at the total synthesis of the antitumor antibiotic cochleamycin A, including intramolecular Diels-Alder cycloaddition reaction and mactolactonization as key steps (Org.
		She is involved with the improvement of the Staudinger ligation of phosphinothioesters with glycosyl azides to form b -glycosyl amides (Org.
		She is also working on the development of chemical reactions of pyrrolysine derivatives.
	www.biochem.wisc.edu /kiessling/lab/lab_members/chang.html (128 words)

	QM/MM tutorial (Site not responding. Last check: 2007-10-29)
		The immune system is triggered by exposing it to a compound that mimicks the transition state of the reaction of interest.
		The generated immunoglobins will strongly bind to the analogue, and, as the analogue is structurally related to the transition state of the reaction, the immunoglobins will posses a certain degree of catalytic activity for that reaction.
		The Diels-Alder cyclo-addition reaction catalyzed by 1E9, a catalytic antibody that was raised against a transition-state analogue compound.
	md.chem.rug.nl /~groenhof/EMBO2004/html/tutorial.html (417 words)

	Melting Point and Diels Alder Reaction
		The Diels-Alder reaction is a cycloaddition reaction in which two molecules add together to form a cyclic compound.
		The reaction will be very rapid leaving you with time to purify your products by recrystalization and to characterize them by IR and melting point.
		With a pure substance, a melting point is the quickest and most accessible method for an organic chemist to confirm the identity of a compound (though in all fairness, NMR is the method of choice due to the proof of identity it provides as well as other information it gives).
	www.owlnet.rice.edu /~chem215/DAMP (1298 words)

	July in Chemistry
		Kurt Alder born 1902: Diels-Alder cycloaddition reaction, Nobel Prize, 1950 with Otto Diels.
		Stanislao Cannizzaro born 1826: His outline of a course in chemical philosophy was instrumental in gaining acceptance of Avogadro's hypothesis and putting atomic weights on a common basis; Cannizzaro reaction in organic chemistry.
		Heinz Fraenkel-Conrat born 1910: separated viral RNA from protein and showed that RNA was the active agent, turning attention to the role of nucleic acids in heredity.
	web.lemoyne.edu /~giunta/July.html (1427 words)

	Wiley::Dienes in the Diels-Alder Reaction
		Covers the intermolecular Diels-Alder reaction, focusing on one of the reactants--the diene.
		The first chapter deals with the fundamental principles of the reaction; the other five chapters describe the salient features of the different classes of dienes and present a wealth of tabulated data.
		In the tables the dienes and the dienophiles are arranged so that the reader can easily find the dienophile and the cycloaddition reactions of interest to him.
	www.wiley.com /WileyCDA/WileyTitle/productCd-0471855499,descCd-description.html (122 words)

	Diels-Alder Reactions of Oxazolidinone Dienophiles Catalyzed by Zirconocene Bis(triflate) Catalysts: Mechanism for ...
		Diels-Alder Reactions of Oxazolidinone Dienophiles Catalyzed by Zirconocene Bis(triflate) Catalysts: Mechanism for Asymmetric Induction
		The Diels-Alder cycloaddition reaction between enoyl-oxazolidinones 3 and dienes is efficiently catalyzed by zirconocene bis(triflate) catalysts (4 and 8) in CH Cl
		Diels-Alder reactions of 3a with, e.g., cyclopentadiene in nitroalkane or dichloromethane solvent are very rapid, even at low catalyst loadings and low temperatures, and rates of reaction cannot be conveniently monitored by
	pubs.acs.org /cgi-bin/abstract.cgi/orgnd7/1998/17/i05/abs/om970916n.html (327 words)

	0130a10
		However, in most reactions, the kinetic and thermodynamic product is the same.
		In this reaction, the products ratio is independent of temperature.
		sterechemistry of the starting dienophile is maintained during the reaction.
	www2.latech.edu /~hji/course251/10jan29/0130a10.html (426 words)

	Brummond Research Group
		"Microwave-Assisted Intramolecular [2 + 2] Allenic Cycloaddition Reaction for the Rapid Assembly of Bicyclo[4.2.0]octa-1,6-dienes and Bicyclo[5.2.0]nona-1,7-dienes" Brummond, K. M.; Chen, D.; Org.
		A Rhodium(I)-Catalyzed Allenic Alder-ene Reaction for the Rapid and Stereoselective Assembly of Cross-Conjugated Trienes," K.M. Brummond; H. Chen; P. Sill, L. You, J. Am.
		A Rapid Synthesis of Hydroxymethylacylfulvene (HMAF) Using the Allenic Pauson-Khand Reaction.
	www.pitt.edu /~kbrummon/pubs.html (519 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		An addition reaction that proceeds in a stepwise fashion.
		A model for the reaction catalyzed by alpha-amino acid decarboxylase.
		The reaction of cyclohexene with Os(O4) followed by treatment of the unstable intermediate with the reducing agent Na2SO3.
	www.chem.vt.edu /chem-dept/castagnoli/FourthExamF2001.doc (1002 words)

	NIH Office of Technology Transfer (OTT) >> Abstract Search
		This invention relates to a new method for the synthesis of conjugate vaccines using the Diels-Alder cycloaddition reaction to covalently attach a carbohydrate antigen from a pathogen to a protein carrier.
		The Diels-Alder reaction has not been extended to conjugation involving biopolymers or other types of polymeric materials.
		In addition to claiming methods of synthesis for conjugate vaccines using the Diels-Alder cycloaddition, the patent application claims vaccines produced utilizing the method, and methods of inducing antibodies which react with the polysaccharides contemplated by the invention.
	ott.od.nih.gov /db/abstxt.asp?refno=165 (186 words)

	MSU Chemistry - Warner Lambert Lectureship 2000
		In 1983, he joined the University of Chicago as an Assistant Pro-fessor, and moved in 1990 to the University of Pennsylvania where he is currently Professor of Chemistry and a member of both the Cancer Center and the Center for Cancer Pharmacology.
		The breadth of Winkler's research activities is underscored by his recent accomplishments in three diverse areas: 1) a highly stereoselective approach to the synthesis of polycyclic com-pounds from acyclic precursors based on the tandem Diels-Alder cycloaddition reaction.
		This methodology has recently been extended to controlled oligomerization using solid-support chemistry; 2) a stereoselective synthesis of methylphenidate (Ritalin) has recently been developed.
	www.cem.msu.edu /lecture_wl_2000.html (443 words)

	Steps Toward Molecular Manufacturing: MBB Skeletons (Site not responding. Last check: 2007-10-29)
		The step-wise syntheses of these skeletons often face severe steric problems at one or more steps, they often have lengthy syntheses, give low yields, and harsh conditions are employed which many functional groups would not tolerate.
		The most promising structures would be the norbornanes, which usually are assembled in one step by a Diels-Alder cycloaddition reaction, starting with two substrate materials that could be functionalized with some limited degree of flexibility.
		But even if this group of compact cage skeletons were easily accessible, one could raise doubts on their usefulness because they might be too small for practical purposes.
	www.n-a-n-o.com /nano/cda-news/skeletons.html (1114 words)

	Wiley::The Diels-Alder Reaction: Selected Practical Methods
		This is the first book to collect together 70 years worth of experimental procedures that have been developed to perfom the Diels-Alder reaction.
		Includes procedures for cycloaddition accomplished in conventional and unconventional media
		The Diels-Alder reaction mechanism was first published in 1928 and in the last 70 years has become the most commonly used and studied mechanism in organic chemistry.
	www.wiley.com /WileyCDA/WileyTitle/productCd-047180343X.html (212 words)

	CSIRO PUBLISHING - Australian Journal of Chemistry (Site not responding. Last check: 2007-10-29)
		A Chemoenzymatic Synthesis of the cis-Decalin Core Associated with the Novel Anti-Mitotic Agent Phomopsidin: Some Observations Concerning a High-Pressure-Promoted Diels–Alder Cycloaddition Reaction of (1S,2R)-3-Methyl-cis-1,2-dihydrocatechol and the Anionic Oxy–Cope Rearrangement of Compounds Derived from the Adduct
		The enantiomerically pure and enzymatically derived cis-1,2-dihydrocatechol 2 engages in a diastereofacially selective Diels–Alder cycloaddition reaction with commercially available lactone 3 at 19 kbar to afford adduct 4, which is readily elaborated to the diene-ol 13.
		Compound 16 also engages in an anionic oxy-Cope rearrangement reaction to give, depending on the molar equivalents of base used, either the cis-decalin 17 or the hexahydroindene 18.
	www.publish.csiro.au /nid/51/paper/CH04036.htm (189 words)

	Recent Literature Examples of Stereospecific Syntheses (Site not responding. Last check: 2007-10-29)
		Here you will find some interesting examples of how the stereochemistry of a product may be maintained during a reaction, without racemization.
		To activate the "hyperactive molecules", you will have to specify a helper for the
		Since thiolesters are readily converted into many other fundamental organic molecules, such as amines, acids, and esters, the above technique has implications for synthesizing these with high diastereoselectivity.
	www.ch.ic.ac.uk /GIC/chirality (118 words)

	The Asymmetric Diels-Alder Reaction (Site not responding. Last check: 2007-10-29)
		Asymmetric Diels-Alder and Ene Reactions in Organic Synthesis,
		Mehta, G.; Uma, R. The Sulfinyl Group as a Chiral Inductor in Asymmetric Diels-Alder Reactions,
		Catalytic Enantioselective Diels ± Alder Reactions: Methods, Mechanistic Fundamentals, Pathways, and Applications
	www.chem.wisc.edu /areas/reich/chem547/_chem547-pericyclic{07}.htm (132 words)

	Sistemes Orgànics
		"Pyrrolodiazines.2.Structure and Chemistry of Pyrrolo[1,2-A]Pyrazine and 1,3-Dipolar Cycloaddition of its Azomethane Ylides"
		"The Parent Diels-Alder Cycloaddition Reaction: A DFT Study of the Concerted and Stepwise Mechanism"
		"Kinetic Isotope Effects as a Guide to Transition State Geometries for the Intramolecular Cope and Ylide Elimination Reactions.
	stark.udg.es /cat/linies/sorg.html (313 words)

	IngentaConnect Table Of Contents: Central European Journal of Chemistry
		Semiempirical PM3 study of Diels-Alder cycloaddition reaction of substituted phosphabenzenes
		Authors: Pacureanu L.; Mracec M.; Simon Z. Bimodality of molecular mass distribution of polydienes obtained under the action of dilithium initiators in hydrocarbon media: the reasons, mathematical simulations, and their experimental testing
		Author: Ananikov V.P. Synthesis of Aldehydes and Ketones by the Dehydrogenation of Alcohols in the Presence of a Raney Nickel/Aluminium Isopropoxide/Alumina Catalyst
	www.ingentaconnect.com /content/cesj/cejc/2004/00000002/00000001 (326 words)

	Diels-Alder Presentation (Site not responding. Last check: 2007-10-29)
		Presentation given by: Angela Liang, Roberto Morales, and Sara Scott
		The Diels-Alder Rxn is a very simple, but elegant reaction.
		However sometimes one of those products is more favored for one reason or another.
	www.umich.edu /~chemh215/W02PRESENT/SSG6/ssg3 (74 words)

	Modern Methods of Organic Synthesis - Cambridge University Press
		For price and ordering options, inspection copy requests, and reading lists please select:
		1.1.2 Conjugate addition reactions of enolates and enamines
		3.3 Cycloaddition reactions with allyl cations and allyl anions
	www.cambridge.org /catalogue/catalogue.asp?isbn=0521778301&ss=toc (88 words)

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