Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
137 Cards in this Set
- Front
- Back
general formula for alkene is?
|
CnH2n
|
|
degree of unsaturation means?
|
how many double bonds it has
|
|
N=1/2(2n + 2-m) is used to determ?
|
the degree of unsaturation
|
|
what formula do use to determ degr of unsat?
|
N=1/2(2n + 2-m)
based on molec CnHm |
|
alkenes are ______________ react than alkanes
|
more
|
|
alkenes are also called?
|
olefins
|
|
what terms can you use to describe alkenes?
|
cis, trans, e and z
|
|
ethylene is?
|
ethene
|
|
propylene is
|
propene
|
|
2 methyl 1 - propene is?
|
isobutylene
|
|
mp and bp of alkenes?
|
incr w incr molec weight
|
|
trans alkenes have ________ mp than cis alkenes
|
higher
|
|
why do trans alkenes have higher mp than cis?
|
they are more symmetr
|
|
trans are less __________ than cis alkenes
|
polar
|
|
cis alkenes have higher bp than trans alkenes due to>?
|
polarity
|
|
in an alkene the _____________ is electroneg and the ________ are electropo
|
double bond is electroneg
alkyl gr are electropos |
|
in trans 2 -butene the dipole moments?
|
cancel each other out
|
|
t or f
cis 2-butene has a net dipole moment |
t
|
|
synth of alkenes
most common way of synth? |
elimination react
of alc or alkyl halides |
|
what 2 things are commonly elimin to make alkenes?
|
1. alc
2. alkyl halides |
|
form alkenes you lose?
|
1. HX
2. H2O |
|
alkenes
eliminat occurs by either? |
E1
E2 |
|
E1 proc thr a ?
|
carbocat intermediate
|
|
E1 the carbocation is a
a. intermed b. transition state |
a. intermed
|
|
E1 rate of react is depend on?
|
substrate
|
|
descr 2 steps of E1?
|
1. leav gr leaves, carbocat is formed
2. proton is remov by base |
|
E1 is favored by?
|
highly polar solv
branch carbon ch good leav gr weak nucleph in low concentr |
|
What mech is competit with E1?
|
Sn1
|
|
E1 and Sn1 are similar in that?
|
they are favor by the same factors
|
|
T or F
low temperat favor E1 |
F
|
|
High or low temper
which favor E1 |
high temperatures
|
|
E2 occurs in how many steps?
|
one
|
|
E2 rate is depend on?
|
concentr of substr and base
|
|
in E2 a _____________ removes a proton and a halide ion ________ to the proton leaves
|
strong base rem
halide ion anit |
|
In E2 the _______________ double bond is preferred
|
more subst double bond
|
|
It is easier to control ______________ than E1 vers Sn1
|
E2 vers Sn2
|
|
E2 is not affected by?
|
steric hindrance
|
|
SN2 is affected by ?
|
steric hindrance
|
|
Highly subst carbon chains will undergo
a. E2 b. SN2 |
a. E2
|
|
SN2 vers E2
strong base fav? |
E2
|
|
E2 vers Sn2
weak lewis base fav? |
SN2
|
|
what things do you modif to fav E2 over E1 and Sn1?
|
1. pol of solv
2. branch of carbon ch |
|
name react of alkenes
|
1. polymerization
2. oxid alkenes to form oxiranes 3. ozonolysis of alkens to cleave double bond 4. oxidat of alkenes w KMnO4- 5. hydroboration with diborane B2H6 and peroxide to make an alcohol 6. adding HX to alkenes thr free radic 7. addit of H2O under acidic condit 8. addit of X2 (halogens) 9. addit of HX 10. reduct using metal catalyst |
|
alkenes can be _________ with molec hydrogen and metal catalyst
|
reduced
|
|
Catalytic hydrog needs?
|
hydrog and metal catalyst
|
|
reduct of alkenes
typical catalysts are? |
platinum, palladium, Raney nickel
|
|
Raney nickel is a ?
|
special powdered form of nickel
|
|
Reduct of alkenes is a __________ addit
|
syn
|
|
in reduct of alkenes the 2 hydrog are added to?
|
same face of double bond
|
|
react where one sterioisomer is favored are called?
|
sterospecific reactions
|
|
electroph addit of alkenes
which bond is weaker? |
pi bond
|
|
Electr on pi bond and are attacked by ?
|
lewis acids
|
|
in electr addit of alkenes lewis acids attack?
|
pi bond
|
|
lewis acids want to accept?
|
an elect pair
|
|
lewis acids are ______________
|
electrophiles
|
|
alkenes
addit of HX electr of double bond act as? |
lewis base
|
|
alkenes
addit of HX first step yields a? |
carbocation
|
|
2 steps of addit of HX to alkene?
|
1. double bond reacts w proton
2. halide ion comb w carbocat |
|
in addit of HX
proton adds to form the most? |
stable carbocat
|
|
addit of HX
proton adds to the ? |
less subst carbon atom
|
|
Why does the proton add to the less subst carbon atom?
|
bec alkyl subst stab carbocat
|
|
addit of HX
markovnikovs rule says that |
proton will add to least substituted carbon,
X will then add to more subst carbon atom |
|
alkenes
addition of hx PROTON WILL ADD TO ? |
less substituted atom
|
|
Markovnikov's rule says that ?
|
a halide, oh-, etc will add to most subst c in double bond
|
|
alkenes
addition of X2 is a ______________ process |
rapid
|
|
what chemical react is used to test for presence of double bonds?
|
addition of X2
|
|
in addition of X2, the double bond acts as a?
|
nucleophile and attacks an X2
|
|
in addition of X2, the intermediate carbocation forms a ?
|
cyclic halonium ion.
|
|
addition of X2 is syn or anti?
|
anit. X- attacks cyclic halonium ion in Sn2 fashion
|
|
addit of X2 in nucleophilic solvent what can happen?
|
solv molec can comp in displ step. prod halo alcohol (and not a dihalo compound)
|
|
addition of X2 in what can make a halo alcohol?
|
nucleophilic solvent
|
|
addition of H2O.
water can be added to alkenes under? |
acidic conditions
|
|
addition of H2O follows what rule?
|
markovnikov rule
|
|
addition of H2O
OH will add to ? |
more subst c of double bond
|
|
addition of H2O is performed at
a. low temp b. high temp |
a. low temp
|
|
why is addit of h2O perf at low temperat?
|
bec otherwise the reverse react will happen.
(acid catalyzed dehydration) |
|
what is the reverse react of addition of H2O to alkene
|
acid catalyzed dehydration
|
|
addition of H2O is carried out indirectly because?
|
bec yield varies w concentration
|
|
How is addit of H2O carried out indirectly?
|
using mercuric acetate
Hg(Ch3COO)2 |
|
what is Hg(Ch3COO)2
|
mercuric acetate
|
|
Free radical addition of HX occurs when?
|
peroxides, oxygen, or oth impurities are pres
|
|
Free radical addit of Hx __________ THE MARKOVNIKOV rule
|
do not follow
|
|
Why dont free rad addit of HX follow the markov rule?
|
bec the X* (radical) adds first to the double bond. making the most stable free radical
|
|
free radical addit to alkenes
is useful for which halides? |
HBR, but not HCL, or HI
|
|
Hydroboroation involves use of ?
|
diborane (B2H6)
|
|
Hydroboration. Diborane.
the boron atom is a ? |
lewis acid
|
|
hydroboration occurs accord to ?
|
antimarkov, syn orientation
|
|
what are the 2 steps of hydroboration?
|
1. addit of boron atom to less ster hind carbon
2. oxidat-hydrolysis w peroxide and aq base |
|
what reagents are needed in hydroboration?
|
BH3,
H2O2, OH- |
|
oxidation of alkenes
is done with? |
KMnO4
|
|
oxidat of alkenes with KMnO4 in cold, dilute produces?
|
1,2 diols (vicinal diols)
|
|
1,2 diols are also called?
|
vicinal diols, glycols
|
|
oxidat of alkenes with potassium permanganate (cold, dilute) makes?
|
1,2 diols (vicinal diols) with syn orientation
|
|
hot basic solut of potassium permanganate, then acidified, what happens to alkenes?
|
1. non term alkenees are cleaved to make a 2 molar equiv of carboxylic acids
2. terminal alkenes are cleaved to form carboxylic acid and carbon dioxide 3. nonterm bond that is disubstituted will yield ketone |
|
With reagants
1.KMnO4, OH-, heat 2. H+ what happens to alkenes |
1. carboxylic acids are prod
2. term double bond prod carbox acid and CO2 3. nonterm double bond w disubst carbon will make ketone |
|
ozonolysis of alkenes uses what reagents?
|
1. O3, CH2Cl2
2. Zn/H2O |
|
ozonolysis of alkenes with ozone and then reduced with zinc and water will prod?
|
the double bond will split and yield aldehydes
|
|
what will this do to an alkene?
1. O3, CH2Cl2 2. NaBH4, CH3OH |
split the double bond and make alcohols
|
|
alkens pxid with ___________ yield oxiranes (epoxides)
|
peroxyacetic acid
|
|
alkens and CH3CO3H or mcpba will yield?
|
oxiranes
|
|
oxiranes are also called?
|
epoxides
|
|
mcpba is ?
|
m-chloroperoxybenzoic acid
|
|
how do you make an oxirane?
|
alkene plus CH3CO3H or mcpba
|
|
polymers are?
|
long chains called polymers of repeating subunits.
|
|
the repeating subunits of polymers are called?
|
monomers
|
|
polymerization occurs thr what mechanism?
|
radical
|
|
give a typical example of polymerization?
|
formation of polyethylene from ethylene (ethene)
req high temp and press |
|
CH2=CH2 with R*, heat, high press will make?
|
RCH2CH2(CH2CH2)n CH2CH2R
a polymer |
|
ethyne is called?
|
acetylene
|
|
suffix _________ is used for triple bonds
|
-yne
|
|
alkynes have ______________ and can be slightly polar
|
dipole moments. but still pretty small
|
|
terminal alkynes are ?
|
acidic
|
|
triple bonds can be made by?
|
1. eliminat of 2 HX from geminal or vicinal dihalide
2. addit of exist triple bond to a nucleophile |
|
eliminat of 2 HX req?
|
high temp and str base
|
|
how do conv a term triple bond to a nucleophile?
|
by remov acidic prot w a str base to prod an acetylide ion
|
|
acetylide ion is used to?
|
add an exist triple bond to carbon skeleton
|
|
partial hydrogenation of triple bonds occurs in what 2 ways?
|
1. lindlars catalyst to make cis isomer
2. sodium in liquid ammonia bel -33 to prod trans isomer of alkene |
|
reduct of alkynes
LIndlars catalyst is? |
palladium on barium sulfate
BaSO4 with quinoline |
|
reduct of alkynes
lindlars catalyst what does quinoline do? |
its a poison that stops the react at the alkene stage
|
|
alkynes
reduct with lindlars catalyst prod? |
alkene with cis isomer
|
|
alkynes
reduct with sodium in liq ammonia bel -33 yields? |
trans isomer of alkene
|
|
alkyne
reduct with sodium and ammonia occurs thr what mech? |
free radical mechanism
|
|
electroph addit to alkynes occurs in a ___________ manner?
|
markovnikov's
|
|
electroph addit to alkynes can be stopped at _______________________ or carried further
|
intermediate alkene
|
|
free radi cal addit to alkynes add with ___________________ orientation
|
anti- markovnikov
|
|
free radical addit to alkyne
intermediate vinyl radical can? |
isomerize to its more stable form
|
|
alkynes can be ________________ with B2h6
|
hydroborated.
|
|
hydroboration of alkynes is?
|
syn, boron atom adds first
|
|
hydroboration of triple bonds
the boron atom can be replaced with a proton from? |
acetic acid
|
|
hydroboration of alkyne.
boron atom can be repl with a proton from acetic acid to make a ? |
cis alkene
|
|
hydroboration
what do you do with terminal alkynes? |
use a disubstituted borane to prev further boration of vinylic intermediate to an alkane
|
|
hydroboration of alkynes
term alkyne-use disubst borane. VInylic borane interm can be? |
oxidately cleaved with hydrogen peroxide
|
|
H2O2 is?
|
hydrogen peroxide
|
|
hydroboration of term alkyne
the interm vinyl alcohol rearranges to make? |
more stable carbonyl compound
|
|
hydroboration of term alkyne
intermediate vinyl alcohol rearranges to more stable carbonyl compound via? |
keto-enol tautomerism
|
|
alkyes can be oxidatively cleaved with?
|
1. basic KMnO4, acidification
2. ozone |
|
oxidat of alkynes will yield?
|
carboxylic acids
|