Stereoisomerism
What is a carbon atom connected to four different groups is known as?
A chiral center
Cation stability ranking
benzylic > allylic > 3 > 2 > 1 > Me
Explain Ozonolysis of alkenes
Dissolving metal reduction of an alkyne will result in what?
a trans alkene
After one round of CCl4, will the halogens be on the same carbon or opposite carbons? What will happen after two rounds?
Opposite carbons; each Carbon will have two Cl atoms
How do you determine R/S of a chiral center?
Give each group a # based on priority and follow 1-2-3 either clockwise (R) or counter-clockwise (S). If group 4 was on a dash, keep R/S. If group 4 was on a wedge, switch R/S.
A cation next to a quaternary carbon indicates that there will be what?
Explain the difference between HBr and HBr, ROOR as reagents?
HBr, ROOR - anti-mark, radical mechanism (no carbocation formed)
For two rounds of H-X to an alkyne, will the Halogens be added onto the same carbon or opposite carbons? Why?
The same carbon. H-X adds mark.
What is the reagent for alkylation of a terminal alkyne?
NaNH2/R-X or NaH/R-X
A spectator chiral center indicates that the stereoisomers will be ___________
Diastereomers
Which of the following alkene addition reactions will add anti-markovnikov?
1. Hydrohalogenation
2. Hydroboration oxidation
3. Hydration
4. Oxymercuration demercuration
5. None (All will add markovnikov)
2. Hydroboration oxidation
What functional group will end up on the most substituted carbon in a Halohydrin formation of alkenes?
A. After the first round, an alkyne that is treated with H2/Pdc will become a __________. After the second round, it will become a _________.
B. What catalyst stops this reaction after the first round?
A. cis alkene; alkane
B. Lindlar's catalyst
Do terminal or internal alkynes have a lower pKa?
Terminal
For a molecule with n chiral centers, what is the maximum number of stereoisomers?
2^n
What is the reagent for oxymercuration demercuration of alkenes?
1. Hg (OAc)2, H2O
2. NaBH2
Give four reagents that may be used in hydration of alkenes.
1. H3O+
2. ROH, H+
3. H+, H2O
4. H2SO4, H2O
The product of reacting an alkyne with H2SO4, H2O / HgSO4 is what functional group? This is due to what process?
Ketone; tautomerization
Do you shift in hydrohalogenation of alkynes if available?
No
How do you convert a Newman projection to a Fischer diagram?
A Fischer is an eclipsed Newman, so if the Newman is staggered, rotate it to eclipsed. The top of the Fischer will be the front of the Newman and the bottom of the Fischer will be the back of the Newman.
What is the reagent for epoxidation of alkenes?
MCPBA or RCO3H
Give four alkene addition reactions that partake in syn addition.
1. Hydroboration oxidation
2. Hydrogenation
3. Epoxidation
4. Dihydroxylation
Give three reagents that would result in hydroboration-oxidation of an alkyne.
1. BH3, THF
2. BBN, H2O2
3. Disiamylborane
A. A terminal alkyne reacted with Disiamylborane will turn into what?
B. An internal alkyne reacted with Disiamylborane will turn into what?
A. Aldehyde
B. Ketone