orgo 3, 4, 5 – Flashcards
Unlock all answers in this set
Unlock answersquestion
| olefins |
answer
| alkenes |
question
| alkenes |
answer
| hydrocarbons that contain a C-C double bond (common) |
question
| alkynes |
answer
| hydrocarbons that contain a C-C triple bond (rare) |
question
| unsaturated |
answer
| alkenes/alkynes have fewer hydrogens per carbon |
question
| suffix for alkenes |
answer
| -ene |
question
| suffix for alkynes |
answer
| -yne |
question
| hybridization of carbons in double bond |
answer
| 3 sp2 hybrid orbitals 120 degree plane p orbital perpendicular to sp2 plane 1 sigma, 1 pi bond |
question
| does free rotation occur in double bonds? |
answer
| no, pi bonds need to be broken first |
question
| cis |
answer
| methyl groups are on the same side of the double bond less stable because of steric strain in the presence of acid changes to trans |
question
| trans |
answer
| methyl groups are on different sides of the double bond |
question
| cis-trans isomerism can't occur if... |
answer
| if one of the double bond's carbon is attached to 2 identical groups |
question
| use EZ naming instead of cis-trans when... |
answer
| double bond has 3 or 4 different substituents |
question
| E |
answer
| higher ranked groups are on opposite sides of double bond |
question
| Z |
answer
| if higher ranked groups are on the side side of the double bond |
question
| Cahn-Ingold-Prelog rules |
answer
| rank groups by atomic number if decision can't be made by first atoms, look at second atoms ect. until you can find difference multiple bonded atoms are equal to same number of single bonded atoms |
question
| addition reaction |
answer
| occur when two reactants add to form a single, new product with no atoms left over |
question
| elimination reactions |
answer
| single reactant splits into two products, mostly a small molecule like H2O or HCl |
question
| substitution reactions |
answer
| occur when two reactants exchange parts to yield two products |
question
| rearrangement reactions |
answer
| occur when a single reactant undergoes a reorganization to yield a single isomeric product |
question
| reaction mechanism |
answer
| how a reaction occurs through bonds breaking/forming, relative rates, how electrons move/reorganize |
question
| how can a covalent bond break? |
answer
| symmetrical, unsymmetrical |
question
| symmetrical break |
answer
| covalent bond breaks so that one electron remains with each product fragment |
question
| unsymmetrical break |
answer
| covalent breaks so that both electrons remain with one fragment, leaving other fragment with vacant orbital |
question
| homolytic |
answer
| symmetrical cleavage |
question
| heterolytic |
answer
| unsymmetrical cleavage |
question
| half-headed/fish-hook arrow |
answer
| shows the movement of one electron symmetrical bond-breaking (radical) |
question
| full-headed arrow |
answer
| shows the movement of two electrons unsymmetrical bond-breaking (polar) |
question
| symmetrical bond-making |
answer
| radical one bonding electron is donated by each reactant |
question
| unsymmetrical bond-making |
answer
| polar two bonding electrons are donated by one reactant |
question
| radical reactions |
answer
| symmetrical movement of single electrons free-radicals |
question
| polar reactions |
answer
| electrons move in pairs more common reaction type occur due to partial pos/neg charges in molecule |
question
| polar bonds |
answer
| made when electron rich atom shares a pair of electrons with electron poor atom |
question
| polar bonds break when... |
answer
| one atoms leaves with both electrons from the former bond |
question
| red electrostatic potential map |
answer
| electron rich (-) |
question
| blue electrostatic potential map |
answer
| electron poor (+) |
question
| curved arrow |
answer
| indicates movement of electrons |
question
| nucleophile |
answer
| nucleus loving attracted to positive charge electron rich (-) neg/neutrally charged lone pairs (lewis base) NH3, water, OH-, Cl- |
question
| electrophile |
answer
| electron loving electron poor (+) forms bonds by accepting electrons (lewis acid) pos/neutrally charged |
question
| are sigma bonds reactive? |
answer
| NO! that's why alkanes aren't reactive because they only have 1 sigma bond |
question
| pi bonds |
answer
| reactive above/below the plane of the molecule it's electron pair behaves as a nucleophile (base) |
question
| carbocation |
answer
| positively charged intermediate specie in a reaction electrophile |
question
| energy diagrams |
answer
| graphically depicts energy changes that occur during a reaction |
question
| vertical axis of energy diagram |
answer
| represents total energy of all reactants |
question
| horizontal axis of energy diagram |
answer
| represents progress of reaction reaction co-ordinate |
question
| reactants (A) |
answer
| energy of the reactants at the start new C-H bond begins to form and H-Cl bond begins to break |
question
| why does energy increase when two reactants collide? |
answer
| electron clouds repel each other |
question
| what is required for a reaction to start? |
answer
| proper orientation and sufficient force of collision |
question
| first transition state (B) |
answer
| structure of maximum energy can't be isolated/directly observed c=c pi bond is partially broken and new C-H bond is partially formed |
question
| activation energy (E act) |
answer
| energy difference between reactants (A) and transition state (B) measures how rapidly reaction occurs |
question
| large E act |
answer
| slow reaction |
question
| small E act |
answer
| fast reaction |
question
| carbocation (C) |
answer
| energy of the carbocation C-H bond is fully formed reaction intermediate entity that is formed during a reaction that reacts further |
question
| second transition state (D) |
answer
| C-Cl bond is partially formed has its own activation energy E act2 |
question
| products (E) |
answer
| energy of the products C-Cl bond is fully formed |
question
| (F) |
answer
| difference in energy between reactants and products |
question
| energy releases |
answer
| reactants has more energy than products |
question
| energy absorbs |
answer
| products have more energy than reactants |
question
| catalyst |
answer
| used as an alternate mechanism when E act can't be reached takes part in reaction, regenerates, goes under no net change increases overall rate of reaction by providing a different pathway |
question
| hydrogenation |
answer
| reaction of alkenes with hydrogen |
question
| enzymes |
answer
| biological catalysts E act has to be low for biological reasons manipulate reaction by providing series of small steps |
question
| uncatalyzed reactions have... |
answer
| large activation energies |
question
| regiospecific reactions |
answer
| reaction where HX is added to alkenes where a mixture is not obtained obeys markovnikov's rule |
question
| morkovnikov's rule |
answer
| H attaches to the carbon with more H's and X attaches to the carbon with more substituents if both carbons have the same # substituents= mixture |
question
| carbocations |
answer
| planar (attack can happen on both sides of plane equally well) pos carbon is sp2 3 substituents are oriented in an equilateral triangle 6 valance e- are used for the 3 sigma bonds p orbitals are above/below plane p orbital is vacant alkyl groups donate e- to pos carbon |
question
| p orbital of carbocations are.... |
answer
| vacant above/below plane |
question
| where do alkyl groups donate their e- to? |
answer
| positively charged carbon atom |
question
| most stable carbocation |
answer
| most substituted attached to more electron rich atom (primary, secondary, tertiary) lower energy |
question
| rank carbocations by increasing stability |
answer
| methyl, primary, secondary, tertiary |
question
| hydration |
answer
| h2o adds to alkenes to yield alcohols takes place on treatment of alkenes with water and strong acid |
question
| protonated alcohol |
answer
| final alcohol with a proton second carbocation in hydration |
question
| hydration reaction conditions are severe because... |
answer
| strong acid and high temperatures are used causes sensitive molecules to be destroyed |
question
| biological hydration requirements |
answer
| double bond to be next to carbonyl group enzyme fumarase to help with hydration during food metabolism |
question
| halogenation |
answer
| halogens, such as Br2 and Cl2, are readily added to alkenes trans |
question
| what does Br2 test for |
answer
| presence of double bonds |
question
| anti-stereochemistry |
answer
| halogenation of alkenes results in trans orientation bromine ties up one face of the ring, forcing the other bromine to the opposite side anti=stereochemical outcome of reaction, not stereochemistry |
question
| planar carbocation + Br2 --> |
answer
| mixture |
question
| haloperoxidases |
answer
| enzymes that carry out halogenation in marine organisms |
question
| hydrogenation |
answer
| addition of hydrogen to an alkene needs a catalyst heterogeneous process (catalyst doesn't dissolve) occurs on surface of catalyst |
question
| reduction |
answer
| hydrogenation addition of H -or- removal of O |
question
| adsorption |
answer
| physical process molecules/atoms stick to surface of catalyst |
question
| complexation |
answer
| chemical process pi electrons in alkene interact with metal through complexation |
question
| syn stereochemistry |
answer
| reduction/hydrogenation cis orientation |
question
| oxidation |
answer
| addition of O -or- removal of H |
question
| oxidized alkenes yield.. |
answer
| epoxides |
question
| epoxide |
answer
| cyclic ether with an oxygen atoms in a three membered ring occurs by treatment of peryoxide, RCO3H |
question
| epoxides |
answer
| oxiranes |
question
| hydrolysis |
answer
| reaction where epoxides undergo acid-catalyzed ring opening reaction with water |
question
| diol |
answer
| product of hydrolysis AKA dialcohol |
question
| glycols |
answer
| diols |
question
| hydroxylation |
answer
| process of epoxidation followed by hydrolysis addition of -OH to each carbon of C=C trans, one face of double bond is blocked trans |
question
| why does protonation of epoxide make it more reactive? |
answer
| C-O bond becomes more polar because of pos charge, susceptible to attack by water |
question
| hydroxylation of alkene in a single step |
answer
| react alkene with KMnO4 in a basic solution cis-diol cleavage |
question
| cleavage |
answer
| separation of double bond (KMnO4 acidic) |
question
| what functional groups are contained after cleavage? |
answer
| carbonyls |
question
| double bond that is tetra-substituted after cleavage... |
answer
| 2 ketones |
question
| if 1 hydrogen is on the double bond after cleavage... |
answer
| one product is a carboxylic acid |
question
| if 2 hydrogens are present on 1 carbon of double bond after cleavage... |
answer
| CO2 is formed |
question
| electrophilic addition |
answer
| electrophile attacks the bond |
question
| polymers |
answer
| large molecule built by repetitive units of monomers |
question
| monomers |
answer
| individual units of monomers |
question
| cellulose |
answer
| polymer built of sugar monomers |
question
| proteins |
answer
| polymers built from amino acid monomers |
question
| nucleic acids |
answer
| polymer built from nucleotide monomers |
question
| polyalkenes |
answer
| made from alkenes using a suitable polymerization catalyst |
question
| alkene polymerization |
answer
| initiation, propagation (repeats), termination |
question
| vinyl monomers |
answer
| many substituted ethylenes that yield polymers propelyne= polypropylene |
question
| conjugated compounds |
answer
| compounds that have alternating double and single bonds HX bonds adds differently than Br2 |
question
| conjugated compound + HX = |
answer
| 1, 2 addition 1, 4 addition |
question
| conjugated compound + Br2= |
answer
| mixture |
question
| allylic carbocation |
answer
| carbocation that is next to double bond more stable than non-allylic carbocations resonance hybrid of 2 forms resonance |
question
| why are allylic carbocations more stable? |
answer
| symmetrical all 3 carbons are sp2 (1 pi 1 sigma) each carbon has a vacant p orbital |
question
| resonance forms |
answer
| two individual carbocation structures <--> don't have to be equivalent |
question
| difference between resonance forms? |
answer
| position of pi bond electrons/lone pairs |
question
| similarities between resonance forms? |
answer
| atoms are in same place atom connections 3d shape |
question
| resonance hybrid |
answer
| allylic carbocation has single unchanging structure that is a blend all its resonance structures characteristics of both structures= share bonds/charges equally more stable than individual resonance forms |
question
| more resonance forms= |
answer
| more stability electrons spread over a larger part of molecule |
question
| resonance does not follow... |
answer
| markovnikov's rule |
question
| movement of lone pairs... |
answer
| movement of charges |
question
| resonance forms follow... |
answer
| octet rule |
question
| alkynes |
answer
| hydrocarbons that contain C-C triple bonds 2 sp (1 sigma, 2 pi) |
question
| alkyne formula |
answer
| CnH2n-2 |
question
| alkyne suffix |
answer
| -yne |
question
| enynes |
answer
| compounds with both double and triple bonds |
question
| alkynes + 2 mol H2 + catalyst= |
answer
| alkenes, then alkanes can be stopped at alkene w/ lindlar catalyst |
question
| alkynes five cis alkenes when reduced because... |
answer
| hydrogenation occurs with syn stereochemistry |
question
| vinylic halide |
answer
| on the C=C |
question
| 1 molar equivalent of HX yields... |
answer
| vinylic halide |
question
| excess of HX yields... |
answer
| dihalide product |
question
| bromine/chlorine + alkynes yields |
answer
| dihalides |
question
| addition proceeds with... |
answer
| stereochemistry (trans) |
question
| product of alkyn+ water |
answer
| ketone |
question
| hydrated internal alkyne yields... |
answer
| mixture of products |
question
| hydrated terminal alkyne yields... |
answer
| one product terminal alkynes are weakly acidic acetylide anion--> terminal alkyne terminal alkyne--> internal alkyne |
question
| acetylide anion |
answer
| formed when strong bases like NaNH2 remove terminal hydrogens react with alkyl halides via nucleophilic attack |
question
| aromatic |
answer
| fragrant |
question
| benzene |
answer
| C6H6 unsaturated substitution reactions planar, sp2, 120, perpendicular p orbitals |
question
| why is benzene less reactive than alkenes |
answer
| resonance makes it more stable |
question
| acetophenone |
answer
| benzene- |
question
| aryl group |
answer
| represents a general aromatic ring |
question
| ortho-disubstituted benzene |
answer
| 1, 2 benzene |
question
| meta- disubstituted benzene |
answer
| 1, 3 benzene |
question
| para-disubstituted benzene |
answer
| 1, 4 benzene |
question
| phenol |
answer
| -OH is at C1 |
question
| toluene |
answer
| -CH3 is at C1 |
question
| electrophilic aromatic substitution |
answer
| electrophile reacts with aromatic ring and substitutes from on the the hydrogen most common aromatic compound reaction less reactive towards electrophiles, needs catalyst |
question
| why does first step of electrophilic aromatic substitution have a high Eact? |
answer
| allylic carbocation isn't as stable as the original benzene ring not as reactive to electrophiles |
question
| what does addition cause in aromatic rings? |
answer
| resonance stability to be lost, need to substitute |
question
| alkylation |
answer
| way to introduce alkyl groups onto benzene ring (Friedel-Crafts) |
question
| Friedel-Crafts alkylation reaction limitations |
answer
| only halogens can be used unless its attached to a ring NO2, CN, SO3H, COR make benzene less reactive |
question
| Friedel-Crafts acylation reaction |
answer
| acyl group is introduced onto benzene ring |
question
| acyl group |
answer
| R-C=O |
question
| activating groups |
answer
| H, OH make benzene ring more reactive donate e- to ring make ring more e- rich causes positive carbocation to be stable Eact lowered, reaction quickened |
question
| deactivating groups |
answer
| NO2, CHO, Cl make benzene ring less reactive withdraw e- from ring makes ring e- poor makes pos carbocation more positive raises Eact, slows reaction |
question
| -OH benzene orientation |
answer
| para, ortho |
question
| -CN bezene orientation |
answer
| meta |
question
| meta directing groups |
answer
| deactivating groups' positively polarized atom is directly attached to ring =O-C-R, O=C-R, C=-N, O-N=O |
question
| ortho, para directing groups |
answer
| activating (excludes halogens) lone pairs on atoms directly bonded to ring OH, NH2, Cl, Br |
question
| how do halogens affect benzene orientation? |
answer
| ortho-para deactivating |
question
| inductive effet |
answer
| withdrawal/donation of e- through a sigma bond due to EN difference between ring's groups |
question
| resonance effect |
answer
| withdrawal/donation of e- through pi bond due to p-orbital overlap between group and benzene ring |
question
| product distribution paralleles... |
answer
| stability of intermediate |
question
| amino group with lone pairs... |
answer
| ortho para mixture |
question
| what part of benzene ring reacts with KMnO4? |
answer
| alkyl groups |
question
| benzylic position |
answer
| place where KMnO4 attack the side chain of C-H bonds next to aromatic ring radical intermediates |
question
| what are aromatic rings inert to? |
answer
| reduction when under typical alkene hydrogenation conditions needs high temp/pressure KMnO4 unless it has alkyl groups |
question
| polycyclic aromatic compound |
answer
| multiple benzene rings fused together |
question
| aromaticity |
answer
| unusual behavior of cyclic conjugated molecules like benzene |
question
| heterocycles |
answer
| aromatic compounds that contain atoms of two or more elements in their rings 6 pi e- pyridine, pyrimidine, pyrrole, imidazole |
question
| pyridine and pyrimidine |
answer
| 1 pi e- on each of their ring's atoms (hexagon) |
question
| pyrrole and imidazole |
answer
| 1 pi e- on each of the 4 atoms and 2 pi e-'s on N-H (lone pair) (pentagon) |
question
| reterosynthetic analysis |
answer
| methodology of working backwards to devise a synthetic route |
question
| nitration of benzene+ HNO3/H2SO4= |
answer
| NO2-benzene |
question
| sulfuration of benzene + SO3/H2SO4= |
answer
| benzene-SO3H |
question
| friedel crafts catalyst |
answer
| AlCl3 |
question
| enol |
answer
| alkyne intermediate rarely isolated |
question
| product of alkyne hydration? |
answer
| ketone |
question
| phenyl group |
answer
| C6H5- |
question
| benzyl group |
answer
| C6H5CH2- |
question
| arylamine |
answer
| ArNH2 |
question
| which ortho/para resonance structure is most stable? |
answer
| lone pairs on oxygen more bonds |
question
| which meta directing ortho/para structure is least stable? |
answer
| one with + closest to the C because this creates too much strain |
