Quiz review on addition reactions Flashcards
What are some of the characteristics of a Addition of HX to alkene?
Acids must be concentrated
Rearrangements are possible
Follows Markovnikovs rule
Uses a X (F, Cl, Br, I) with a hydrogen to end up adding both to the alkene
What are some of the characteristics of a Addition of HX to alkyne?
Concerted mechanism
Follows Markovnikovs rule
Can stop at vinyl halide or continue to geminal alkyl dihalide.
Adding of X to a triple bond and triple bond adds to a H-X. If there is an excess, the reaction can go again and bind 2 X
What are the identifying characteristics of Addition of H2O and ROH to alkene?
Requires a catalytic strong acid
Markovnikovs rule
Rearrangement possible
Addition of HO or RO to the alkene with the help of an acid
What are some of characteristics of an addition of H2O and ROH to an alkyne?
Concerted mechanism
Markovnikovs rule
Only water
Reaction creates what is called an enol, which is an oh on a single bond and double bond on a downstream carbon. The reaction doesn’t care for this, so it converts it to a ketone.
What is Tautomerization?
The interconversion between an enol and a ketone.
What is taautomers
The enol and keto forms of a molecule, not resonance structures.
What are the characteristics of a hydroboration-oxidation reaction of an alkene?
Concerted mechanism
Anti Markovnikovs rule
Syn addition
Product created is with the addition of a H2B and a hydrogen molecule, then the H2B turns into a HO molecule.
What are the characteristics of the hydroboration oxidation of an alkyne?
Concerted mechanism
Anti Markovnikovs rule
Syn addition.
Creates the same produce as does the alkene version, just with a double bond on a O group. That is then an enolate, with the double bond sliding over to the O group to become an aldehyde.
What are the characteristics of a epoxidation of alkene?
Concerted mechanism
Syn addition
mCPBA is the most common reagent (peracid works too)
The oxygen that is creates a sort of triangle bond with the other bonds in the system
Halogenation of alkenes characteristics
Stepwise, but no carbocation intermediate
Halonium ion intermediate
Anti addition
Doesn’t work with F2
Adding a X2 molecule to one side in the triangle format, then the other molecule does backside attack to do anti addition
Halogenation of alkynes characterstics?
Mechanism similar to halogenation of alkenes but much slower
Anti addition
Can stop of vicinal dihalide or go to tetrahalide
Same as alkene on front half, but can continue further if there’s an excess.
Halohydrin formation from an alkene characteristics
Similar to halogenation but,
Nucleophile in second step is H20 and ROH
Usually an excess of solvent.
H2O/ROH adds to more substituted carbon
Adds the X and Solvent on anti addition in 2 stereoisomers.
Halohydrin formation from an alkyne characteristics
Similar to Halohydrin of alkenes and halogenation of alkynes, but
Intermediate is an enol, which tautomerizes to the ketone.
Anti addition of a X and OH group, then the conversion to a ketone.
Dihydroxylation of alkenes characteristics.
There are two possible stereoisomers for this, anti and syn.
It is a two step process, where an RCO3H gives a oxygen that is syn bound, then split into two anti OH groups by H3O+
In Syn dihydroxylation, OSO4 or KMnO4 is added and two OH groups are added simultaneously to be syn.
Acidic ring opening of epoxides characteristics
Anti addition
Nucleophile adds to more substituted carbon.
Mechanism shows the addition of a hydrogen to a O cyclopropane, with then the addition of water to break the ring.
