distillation
cis-trans isomers of alkenes are configurational stereoisomers that can be separated from one another by what process? (taking advantage of the difference in their boiling points)
light or heat
the required energy to break the pi bond in geometric isomers of alkenes may be in the form of (?)
no
does the conversion of cis to trans occur under normal laboratory conditions?
addition reaction
the most common reaction with alkenes
this process is product-favored because the products are more stable (sigma bonded)
Includes:
Halogenation
Hydration
Hydrohalogenation
acid catalyst
if this is present in hydration, water adds to alkenes, and the products are alcohols
acids
various (?) can add to double bonds of alkanes
unsymmetric
if both the reagent and the alkene are (?), 2 products are possible
regioisomers
a class of constitutional isomers which have the same functional groups but attached at different positions
regiospecific additions
produce only 1 regioisomer
regioselective additions
one major regioisomer is produced, while the other is present in only trace amounts
Markovnikov’s Rule
When an unsymmetric reagent is added to an unsymmetric alkene, the electropositive part of the reagent bonds to the carbon of the double bond that has the greater number of hydrogen atoms attached, or the more electronegative part of the reagent bonds to the carbon of the double bond that is more substituted (less hydrogen)
electrophilic addition
A reaction in which an electrophile is added to an alkene
electrophiles
“electron lovers”
Electron-poor reagents
Seeks electrons
e.g. often cations, electron-deficient
species, Lewis acids
nucleophiles
“nucleus lovers”
Electron-rich reagents
form bonds by donating electrons to an electrophile
e.g. electronegative elements, Lewis bases, negatively-charged species, has multiple bonds
nucleophile
the (?) can act as a supplier of pi electrons to (?)
nucleophile
in the electrophilic addition of alkenes, the C=C double bond acts as a (?) due to its pi electrons
proton (H+)
what serves as the attacking electrophile?
2
in the Mechanism of Electrophilic Addition of Alkenes, as the proton approaches the pi bond, (?) pi electrons form a sigma bond between the proton and one carbon atom
unstable and reactive
carbocations are highly (?) because there are only six electrons around the positively- charged carbon (NOT OCTET)
increases
Carbocation stability (?) as the number of adjacent alkyl groups increases.
inductive effects
(an explanation for carbocation stabilization)
an alkyl group can share electron density with an adjacent carbocation, therby stabilizing it
hyperconjugation
(an explanation for carbocation stabilization)
electrons in the C-H bonds of adjacent carbon atoms can overlap with the empty p-orbital of the carbocation (as long as they are planar)
stabilizing
the interaction between a bonding orbital and an empty p-orbital is (?)
alkyl halide
what is the product of hydrohalogenation?
alcohol
what is the product of the hydration mechanism?
pi bonds
halogens react with what bonds due to their polarizability?
vicinal dihalide
what is the product of the halogenation of alkenes?
hydroboration
the addition of borane (BH3) to an alkene, forming alkylborane
less
in hydroboration (unsymmetrical alkenes), the boron atom bonds to the (?) substituted carbon atom
alcohol
what is the product of the hydroboration-oxidation of alkenes?
metal catalyst
in the reduction of alkenes, the addition of H2 occurs only in the presence of a (?)
conjugated diene
(type of diene)
double bonds are separated by one single bond
sometimes called as 1,3-dienes
1,3-butadiene is the simplest
isolated diene
(type of diene)
double bonds are separated by more than one single bond
cumulated diene
(type of diene)
double bonds are adjacent
allylic carbocation
A carbocation with a carbon-carbon double bond adjacent to the positive carbon
concerted reaction
a reaction in which all bond-breaking and bond-making occur at the same time
diels-alder reaction
the reaction between a conjugated diene and an alkene (dienophile) to form unsaturated six-membered rings
dicarbonyl compound
for a cycloalkene, oxidative cleavage results in a single molecule with 2 carbonyl groups, or a (?)
epoxide
cyclic ether with a three-membered ring
contains an oxygen atom attached to two adjacent carbon atoms of a hydrocarbon
terminal alkyne
alkyne that has at least one hydrogen atom directly bonded to each of the carbon atoms involved in the triple bond
require the presence of an additional Hg2+ catalyst (usually HgSO4) to yield methyl ketone by Markovnikov's addition of water
internal alkyne
alkyne that has no hydrogen atoms directly bonded to either of the carbon atoms involved in the triple bond
undergo hydration with a concentration sulfuric acid to form ketones
vinyl halide
Has a halogen atom directly attached to a carbon atom within a carbon-carbon double bond (C=C)
addition of one mole
geminal dihalide
has 2 halogen atoms directly attached to the same carbon atom
vinyl halide reacts with a second mole of HX to form this
sp hybridized C—H bonds
what is the most acidic among sp, sp2, and sp3 hybridized C—H bonds?
strong base
terminal alkynes are readily deprotonated with (?) in a Bronsted-Lowry acid-base reaction
acetylide ion
resulting ion from the deprotonation of terminal alkynes with a sufficiently strong base
they can react with a variety of electrophiles