Reactions of Alkenes Flashcards

Chemical bond
Terms Definitions
H2O, H2SO4
alcohol
KMnO4, H2O
cis diol
Indirect Hydration
1. Oxymercuration-Demercuration
2. Hydroboration
CH3-CH(OH)-CH3 --> ? + H2O
CH3-CH=CH2
BH3 ; THF reagent
hydroboration reagent
CH2=CH2+ H2 is called ______ reaction
hydrogenation
H-Br + R-O-O-R
Anti-Markelov product, radical addition of bromine
marks rule
hyderogen goes to more hydrogen (HBr,HCl,HI)
hydroboration
addition of borane, (BH3), to an alkene, to form a trialkylborane
CH2=CH-CH3 + HI --> what is the product?
CH3-CH(I)-CH3
Removal of 2H atoms from adjacent C atoms
Dehydrogenation
Hydrogenation
Alkene + H2 = Alkane. Need METAL catalyst. SYN addition
oxymercuration-reduction
a method for converting an alkene to an alcohol. The alkene is treated with mercury (II) acetate followed by reduction with sodium borohydride
Hydration (Hydroboration)
1) BH3 (THF)/ 2)Peroxide. Opposite of Markovnikov stereochemistry. OH on Carbon with MOST hydrogens. Releases steric strain.
Addition of H and OH across a double bond
Hydration
alkoxymercuration-demercuration (mark product)
converts alkenes to ethers by adding an alcohol across the double bond of the alkene
Alkyne + H-X
In a terminal alkyne, Markalov's rule addition. In an internal alkyne, mixture of M and anti-M products.
Alkene Cleavage (Permanganate)
KMnO4/ Acid. Puts Oxygen on double bonds and between any C-H bonds remaining. CH2 turns into CO2.
catalytic reduction/catalytic hydrogenation
conversion of an alkene to an alkane involves reduction by hydrogen in the presence of a catalyst
Alkene Cleavage (Ozone)
O3/ Zn, Acid. Cuts double bond and plugs with Oxygen.
Alkyne + KMnO4 + H2O, hot
Oxidative cleavage, with each carbon double bonded to an oxygen, and bonded to an oxygen.
Mechanism of HBr + ROOR + Alkene
ROOR forms two free rads that attach to the H from HBr. Br free rad breaks C=C by attacking C. Most stable C free rad formed, which then grabs an H. ANTIMark!
HX
alkyl halide
ANTI additions
oxymercuration-demercuration, halogenation, halohydrin
hydrogenation catalyst (syn add)
Pt,Pd,Ni
CH3-CH(X)-CH(X)-CH3 --> ? + X2
CH3-CH=CH-CH3
oxidation
loss of electrons; alternatively, either the loss of hydrogens, the gain of oxygens, or both
Hydroboration reagents
1. BH3
2. H2O2, OH-
Addition of two hydrogen atoms across a double bond
Hydrogenation
anti-mark
addition of HBr in presence of peroxides ( ROOR) H does not go to more hydrogens goes to less H
glycol
a compound with hydroxyl (-OH) groups on adjacent carbons
CH2=CH2 + HBr is called ______ reaction
is hydrohalogenation
Hydration
H2O adds to alkene by breaking double bond and having H and OH attach to vicinal Cs. Forms alcohol. Markovnikov product.
OsO4 + H2O2
Syn addition of OH. Dihydroxylation. Reverses stereochemistry
Hydration (oxymercuration)
1) Hg(OAc)2/ 2) NaBH4. Mercury fills the H+ position from an acid, but forms a bridge like bromine, forcing OH into the Markovnikov orientation. Its then replaced by a hydrogen.
Stereospecificity in Halogenation
Cis gives racemic mixture. Trans gives meso product. OPPOSITE OF HYDROXYLATION STEREO.
nucleophile
an yspecies that can donate a pair of electrons to form a a new covalent bond; alternatively, a Lewis base
Alkyne + Sia2BH (disiamylborane) + H2O2 +NaOH
Anti-Markelov hydrogenation, with Sia2B binding with the alkyne and H2O replacing it.
Diol (Oxidation)
OsO4/ NaHSO3. Syn addition of 2 -OH groups. Via Cyclic Osmate intermediate.
addition reaction
a reaction in which two atoms or ions react w/ a double bond, forming a compound w/ the two new groups bonded to the carbons of the original double bond
Carbenoid Addition (Simmons Smith)
CH2I2 / Zn(Cu). Forms a cyclopropane over the double bond. Not a Carbene, but carbene-like carbenoid.
Alkyne + H2O+ HgSO4 + Acid
Enol ( OH-CR=CR'R"), which quickly becomes a ketone ( O=CR-CHR'R")
BH3, H2O2, OH
alcohol
H2 + metal catalyst
alkane
mCPBA or MMPA
epoxide, carboxylic acid
Halogenation
ANTI addition, so it's stereospecific!
CHX3
Alpha elimination, is first dehalohydrogenated, then both carbons in alkene bond to halo-form.
reduction
the gain of electrons, alternatively, either the gain of hydrogen, loss of oxygens, or both
Hydrohalogenation
Alkene plus HX. Pi bond broken, Markovnikov H, stable carbocation formed, X attaches to carbocation.
stereospecific reaction
a special type of stereoselective reaction in which the stereochemistry of the product is dependent on the stereochemistry of the starting material
electrophilic additions
electrophile starts the addition to the alkene; is an addition reactionwhere, in a chemical compound, a π bond is broken and two new σ bonds are formed. electrophile starts the addition of the alkene
CH2=CH2 + Cl2 is called _______ reaction
is halogenation
CH3-CH=CH-CH3 + HBr --> What is the product?
CH3-CH(Br)-CH2-CH3
rate-determining step
the step in a multistep reaction sequence that crosses the highest energy barrier
Alkyne + H2 + Lindlar's Catalyst +Quinoline
Cis alkene
Hydrogen adds to the carbon of the double bond having the greater number of hydrogens is the ___________ rule
Markonikov's rule
marks rule extended
in an electrophilic addition to an alkene, the electrophile adds in such a way as to generate the most stable intermediate
syn stereoselective
the addition of atoms or groups of atoms to the same face of a C-C double bond
H2O + Acid
Hydration, Markelov addition of an OH group.
Halogenation mechanism
Pi electrons break the Br2 and make Br free rads. One Br forms a triangle with 2 Cs, so the other Br has to attack on the other side. 2 steps.
Alkyne + KMnO4 + H2O
Diketone, with each carbon double bonded to an oxygen.
Halohydrin Formation mechanism
Pi electrons break the X2 and make X free rads. One X forms a triangle with 2 Cs, so the water has to attack on the other side. 2 steps. X will follow Mark's rule: go to C with most Hs.
halohydrins (mark extended) anit add(CL,Br)
an alcohol with a halogen on the adjacent carbon atom. in water halogens add to alkenes to form halohydrins
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