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Topic: Carbon nucleophile

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	Encyclopedia: Nucleophile
		A nucleophile participates in a chemical reaction by donating electrons to a species known as an electrophile in order to form a chemical bond.
		Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge on an element and displaces the group it is bonded to.
		Nucleophilic is an adjective that describes the affinity of a nucleophile to the nuclei, while nucleophilicity or nucleophile strength refers to the nucleophilic character.
	www.nationmaster.com /encyclopedia/Nucleophile (870 words)

	Media Portfolio
		In an alkyl halide, the halogen atom is bonded to an sp3 hybrid carbon atom.
		The carbon atom of iodomethane is electrophilic because it is bonded to an electronegative iodine atom.
		Nucleophilicity is defined by the rate of attack on an electrophilic carbon atom.
	wps.prenhall.com /wps/media/objects/340/348272/wade_ch06.html (3055 words)

	Nucleophile (Site not responding. Last check: 2007-10-17)
		In chemistry, a nucleophile (literally nucleus-lover) is a reagent attracted to nuclei that participates in a chemical reaction by donating electrons in order to bond to a substance.
		Nucleophiles take part in nucleophilic substitution, whereby a nucleophile becomes attracted to the nucleus of an element and displaces the group it is bonded to.
		Nucleophilic is an adjective that describes the affinity of a nucleophile to the nuclei, while nucleophilicity refers to the nucleophilic character.
	www.eurofreehost.com /nu/Nucleophile.html.txt (228 words)

	Grignard Synthesis
		A carbon nucleophile would need to have an unshared pair or a bonding pair in which the polarity of the bond was such that the carbon was a strongly negative end of the dipole.
		Since we have learned that the carbonyl carbon of aldehydes reacts as an electrophile, we must conclude that the carbon which started out attached to the bromine is behaving as a nucleophile.
		In the bottom reaction, the depiction of this bond is taken to an ionic extreme in which the electron pair is shown as entirely belonging to the carbon, which emphasizes the carbon's nucleophilic character.
	chemistry2.csudh.edu /rpendarvis/grignard.html (1716 words)

	Encyclopedia: Grignard reagent
		In chemistry, a carbonyl group is a functional group composed of an atom of carbon double-bonded to an atom of oxygen.
		The Barbier reaction is an organic reaction between a alkyl halide and a carbonyl group as an electrophilic substrate in the presence of aluminium, zinc, indium, tin or its salts.
		The Bouveault aldehyde synthesis is a one-pot chemical reaction that converts a primary alkyl halide to an aldehyde one carbon longer.
	www.nationmaster.com /encyclopedia/Grignard-reagent (1350 words)

	[No title]
		An electon pair from the nucleophile forms a new bond to the carbonyl carbon, and this forces two electrons from the carbon-oxygen double bond to move onto oxygen.
		The carbonyl carbon rehybridizes from sp2 to sp3, and the intermediate that is formed has a tetrahedral geometry.
		With nucleophiles such as amines, though, the oxygen component can be completely expelled via loss of an equivalent of water to form a double bond between carbon and the nucleophile (an imine if the nucleophile was an amine).
	www.chem.wisc.edu /~newtrad/CurrRef/AIDStopic/AIDS.AldKetRxns.html (2217 words)

	Fats & Soaps
		This is followed by attack of the nucleophilic alpha carbon of the enolate on the carbonyl carbon of a second molecule of the ester.
		That is, attack by nucleophilic carbon atom at the carbonyl carbon of an ester, which is followed by loss of the alcohol portion of the ester as a leaving group.
		The four carbon ester which is thus produced is attacked at its carbonyl carbon by another molecule of the carbon nucleophile and the cycle continues.
	chemistry2.csudh.edu /rpendarvis/ester-fats.html (1715 words)

	Nucleophilic Substitution Reactions
		Nucleophilic substitution will be explored in much more detail in chapter 8.
		In the reactions of alcohols with HX, the reactivity trend of HI > HBr > HCl > HF is not due to the nucleophilicity of the halide ion but the acidity of HX which is involved in generating the leaving group prior to the rate determining step.
		Since the nucleophile is involved in the rate determining step, the nature of the nucleophile is very important in an S
	www.mhhe.com /physsci/chemistry/carey/student/olc/ch04nucle.html (1065 words)

	SparkNotes: Introduction to Organic Chemistry IV: Leaving Groups and Nucleophiles
		Nucleophilicity is defined by the rate constant of its substitution reaction.
		Thus nucleophilicity is a kinetic variable, while basicity is a thermodynamic one.
		Protic solvents decrease nucleophilicity by hydrogen bonding to the nucleophile's lone pair end.
	www.sparknotes.com /chemistry/organic4/intro/section2.rhtml (514 words)

	wiki/Ketone Definition / wiki/Ketone Research (Site not responding. Last check: 2007-10-17)
		A carbonyl carbon bonded to two carbon atoms distinguishes ketones from carboxylic acids, aldehydesAn aldehyde is either a functional group consisting of a terminal carbonyl group, or a compound containing a terminal carbonyl group.
		A carbon atom adjacent to a carbonyl group is called an α carbon.
		This provides the carbon with four temporary bonds, one of which is broken when the leaving group leaves, and another which is formed by formation of a double bond....
	www.elresearch.com /wiki/Ketone (3135 words)

	lesson2
		This is because of the electrophilic carbon atom on the structure.
		Then the nucleophile continues to push until the carbon nucleophile bond is complete and the carbon bromine bond is broken.
		The nucleophile of course, is the species in the reaction that has either a lone pair of electrons (or extra electrons) and possibly a negative charge.
	www.gpc.edu /~lstrange/2642/onlinelessons/lesson2better.html (667 words)

	[No title] (Site not responding. Last check: 2007-10-17)
		A transition state is formed in which the bond between the nuclophile and carbon atom is being formed at the same time the bond between the carbon atom and the leaving group is being broken.
		Steric hindrance to backside attack of the nucleophile is most significant in tertiary halides and decreases as alkyl groups are replaced by hydrogen atoms.
		Backside displacement of the leaving group by the nucleophile accounts for the observation that reaction of a nucleophile at a chiral center leads to a product with the opposite arrangement of groups, a process called inversion of configuration.
	people.uis.edu /gtram1/organic/alkylHalides/sn2.htm (299 words)

	[No title] (Site not responding. Last check: 2007-10-17)
		Nucleophilic Substitution The nucleophile Nuc:- displaces the leaving group X- from the carbon atom by using its lone pair to form a new bond to the carbon atom.
		The carbon atom is electrophilic since it is bound to a (more electronegative) halogen, which pulls electron density away from the carbon, thus polarizing the bond with carbon bearing partial positive charge and the halogen bearing partial negative charge.
		Carbon can only have a maximum of 8 valence electrons, so as the carbon-nucleophile bond is forming, then the carbon-leaving group bond must be breaking.
	crab.rutgers.edu /~alroche/Ch06.doc (3510 words)

	Alkyl Halide Reactivity
		Because the functional carbon atom has been reduced, the polarity of the resulting functional group is inverted (an originally electrophilic carbon becomes nucleophilic).
		The nucleophilic carbon of these reagents also bonds readily with electrophiles such as iodine (second equation) and carbon dioxide (fifth equation).
		The last example, in which two halogens are bonded to the same carbon, referred to as geminal (twinned), gives an unusual reagent which may either react as a carbon nucleophile or, by elimination, as a carbene.
	www.cem.msu.edu /%7Ereusch/VirtualText/alhalrx4.htm (1426 words)

	Carbon oxygen multiple bonds and their reactivity (Site not responding. Last check: 2007-10-17)
		The carbon oxygen double bond is very versatile and is the cornerstone of the much synthetic chemistry.
		To a first approximation it is similar to a carbon carbon double bond.
		hybridised, the carbon oxygen distance is 1.23Å, compared to 1.33Å for a carbon carbon bond.
	speedy.st-and.ac.uk /~naismith/teaching/lectures/ch1004/topica3.htm (1106 words)

	[No title]
		The interconversion of ketones to amine derivatives is a key step in metabolism in the exchange of carbon skeletons and nitrogen in cells, such as in the breaking down and synthesis of amino acids.
		This is an SN2 reaction, with the phosphorus atom acting as the nucleophile.
		In the second step, a strong base removes the proton on the carbon attached to P, to form a phosphorus ylide (an ylide is a molecule in which a charge separation between two adjacent atoms exists in the stable form.) The partially anionic carbon formed then adds to the carbonyl in a nucleophilic addition.
	academic.evergreen.edu /curricular/m2o2002/carbonyl.doc (998 words)

	[No title]
		The general mechanism of nucleophilic addition is the nucleophile forms a new bond to the carbonyl-group carbon, the carbon-oxygen double bond breaks, and a proton bonds to the oxygen.
		Imines are formed by the nucleophilic addition to the carbonyl group by the nucleophilic amine, followed by the loss of water from the amino alcohol addition product.
		One carbonyl component with an alpha-hydrogen atom on the alpha-carbon, the carbon bonded to the carbonyl carbon, is converted by base into its enolate ion.
	www.clas.ufl.edu /users/tmullins/BCH3023/fall98/lecturenotes6.html (651 words)

	Chemistry Department, Marquette University
		Through these studies we have observed nucleophilic attack at both the terminal carbon atoms (path a) and at internal positions (path b).
		heteroatom nucleophiles, or organolithiums, or stabilized carbon nucleophiles).
		Where these reactions proceed with high regioselectivity, they can be utilized for the formation of carbon- nucleophile bonds in the synthesis of compounds of biological interest (eg.
	www.marquette.edu /chem/personnel/faculty/donaldson.html (368 words)

	Chemical Reactivity (Site not responding. Last check: 2007-10-17)
		A third resonance contributor, which has the negative charge on the central carbon atom, has been omitted from this drawing, but is an important factor in alkylation reactions of beta-dicarbonyl compounds.
		From this formula it should be clear that nucleophiles may bond either at the carbonyl carbon, as for any aldehyde, ketone or carboxylic acid derivative, or at the beta-carbon.
		Although nucleophilic addition reactions to alkenes are usually slow, conjugation with a carbonyl or nitrile function vinylagously activates the beta-carbon, resulting in rapid addition.
	www.cem.msu.edu /~reusch/VirtualText4/special2.htm (6085 words)

	[No title] (Site not responding. Last check: 2007-10-17)
		The two methyl groups on the electrophilic carbon of 2-chloropropane (isopropyl chloride) sterically hinder the approach of a nucleophile to the electrophilic carbon (blue) from the side opposite the leaving chlorine (green).
		When the chlorine is on a tertiary carbon, the steric hindrance at the electrophilic carbon (blue) is so great that that the nucleophile cannot approach from the side opposite to the leaving chlorine (green).
		Even though the chlorine is on a primary carbon in neopentyl chloride, it is very difficult for a nucleophile to approach the electrophilic carbon (blue) from the side opposite the leaving chlorine (green) because of the large tert-butyl group that is bonded to the electrophilic carbon.
	www.du.edu /~jhornbac/organic/stersn2.html (254 words)

	Organic Chemistry 341 Notes
		The rate of the reaction depends on both the substrate and the nucleophile, and is described by rate equation below.
		since the nucleophilic attack at the carbon is involved in the transition state, the sterics of the substrate are important.
		Stronger nucleophiles react faster - anionic nucleophiles will be stronger than neutral - that is, H2O is a poor nucleophile compared to -OH.
	www.ndsu.nodak.edu /instruct/grcook/chem341_98/lectures/lecture31.shtml (234 words)

	Carbanions
		Organic chemists are interested in generating nucleophilic carbon because the formation of carbon-carbon bonds lies at the heart of organic synthesis, and the vast majority of carbon-carbon bond forming reactions involve the coupling of a nucleophilic carbon with an electrophilic carbon.
		The term carbon acid refers to any species in which a hydrogen atom may be transferred to a base as shown in Figure 1.
		This allows for maximum overlap between the orbitals on the carbon and those of the adjacent pi bond; electron density is transferred from the carbon to the oxygen, thus stabilizing the anion.
	usm.maine.edu /~newton/Chy251_253/Lectures/Carbanions/Carbanions.html (1330 words)

	Synthesis of C-glycosylated compounds with the use of a mild, iodine-catalyzed reaction - US Patent 5414074 (Site not responding. Last check: 2007-10-17)
		The invention concerns C-glycosylated derivatives of soft carbon nucleophile compounds, particularly compounds which contain acid-labile structural units, and more particularly, C-glycosylated derivatives of known compounds that are useful pharmacological agents such as antibiotics, antineoplastic compounds and antiviral compounds.
		Preferred soft carbon nucleophiles comprise a compound or a moiety selected from members of the group consisting of enolate derivatives having the formulas a) to w) ##STR2## and allyl, vinyl, alkynyl and propargyl silanes and stannanes, and MCN; wherein M represents ##STR3## R, R
		Preferred nucleophiles are precursors of showdomycin, ravidomycin, formycin, and analogs thereof.
	www.patentstorm.us /patents/5414074.html (1693 words)

	Palladium-catalyzed coupling of aryl halides, non-conjugated dienes and carbon nucleophiles - Patent 5164518
		The present invention provides a method for the alpha,omega-arylation/alkylation of a non-conjugated diene in one step by reacting the diene with an aryl iodide or an aryl bromide and a carbon nucleophile in the presence of an amount of a Pd(O) complex effective to catalyze the reaction.
		In such reactions,.pi.-allylmetal complexes frequently play an important role because of their high reactivities toward various nucleophiles, which result in transfer of the allyl groups from the metal to the nucleophiles.
		The compounds of formula I are apparently formed by arylpalladium generation and addition to the less substituted end of the diene, palladium migration down the carbon chain to form a.pi.-allylpalladium intermediate, and carbanion displacement of the palladium moiety.
	www.freepatentsonline.com /5164518.html (1961 words)

	Widenhoefer Lab - Research
		Our approach to the transition metal-catalyzed addition of a stabilized carbon nucleophile to an unactivated olefin employed activated methylene compounds, as opposed to stabilized carbanions, as the carbon nucleophile and simple Pd(II) complexes as the catalysts.
		This approach was based on the expectation that the enol tautomer of an activated methylene compound would be sufficiently nucleophilic to attack an olefin in the presence of Pd(II) and yet avoid the compatibility issues associated with stabilized carbanions.
		For example, treatment of alkenyl indole of 8 with a catalytic 1:1 mixture of the sterically bulky platinum BIPHEP complex (R)-9 and AgOTf at 60 °C for 24 h led to the isolation of tetrahydrocarbazole 10 in 93% yield with 90% ee (eq 5).
	www.chem.duke.edu /~rwidenho/research.htm (1551 words)

	Haloalkanes (Organic chemistry) - Wikibooks
		The nucleophile replaces the halogen, an electrophile, which becomes a leaving group.
		First, the electrons in the nucleophile attack the central carbon atom from the side opposite the leaving group (in this case, a halogen).
		The electrons forming the bond between the central carbon atom and the halogen move to the halogen, causing the halogen to leave the molecule.
	en.wikibooks.org /wiki/Haloalkanes_(Organic_chemistry) (892 words)

	Skill Development Exercises (Site not responding. Last check: 2007-10-17)
		The nucleophile produced by deprotonation of a terminal alkyne is very similar to a Grignard reagent.
		Strong nucleophiles such as Grignard reagents are known to attack the C of a C=O (carbonyl group).
		The electronegativity of oxygen steals electron density away from carbon leaving this "carbonyl carbon" with a large partial positive charge.
	home.earthlink.net /~cuachemistry/organic/SDEAns/AnsSDE23.htm (420 words)

	Enolates and the Aldol Reactions
		One way to describe what we have just done is to say that we have worked out a way to make the alpha-carbon of a carbonyl compound into a carbon nucleophile.
		Earlier we found that the carbon nucleophile of a Grignard reagent was very important as a synthetic tool.
		Since that carbon already lost one hydrogen in forming the enolate intermediate essential to the aldol addition, it must have had two hydrogens in the original aldehyde.
	chemistry2.csudh.edu /rpendarvis/a-carbaldol.html (971 words)

	Chem2OB3 - Experiment 4
		The aldol reaction involves condensation of two carbonyl compounds, one of which serves as the nucleophile and the other as the electrophile in the first step.
		The one serving as the nucleophile must have hydrogens on the carbon adjacent to the carbonyl group.
		Removing one by reaction with a base generates an enolate ion, which is a potent carbon nucleophile (much like a Grignard reagent).
	www.chemistry.mcmaster.ca /courses/2ob3/nhw_temp/old_old_labmanual/2001_exp3.html (1015 words)

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