1) Draw the major organic product of the following reaction, name it, and then tell whether the product is produced as a single stereoisomer, a racemic mixture or as a mixture of diastereomers. 1. BH3•THF
2. H2O2, OH–
2) Find the major organic product of each of the following chemical reactions. Include stereochemistry using wedge-­‐dash formalism whenever stereoselecctivity is expected. HBr
CH2Cl2
A)
Br2
EtOH
B)
1. Hg(OAc)2, H2O, H2SO4
2. NaBH4
C)
H 2O
H 2SO 4
D)
3) Draw the major organic product of the following reaction sequences. Br 2
hν
A)
1. BH3•THF
LDA
2. H2O2, OH–
(LiN[CH(CH3)2]2
4) Draw the curved arrow mechanism of the following intramolecular reaction. Br
Br2
A)
HO
+ HBr
O
Retrosynthesis: 5) In each of the following, find the immediate precursor to the product shown and give the conditions under which the precursor is transformed to the Target Product Shown on left of arrow. OH
?
Target
A)
Immediate Precursor
Reactants
Br
X
B)
Y
O
OH
X
C)
H3C OH
Br
Y
X
D)
E2
6) Propose a sequence of reactions by which the following chemical transformation may take place in high yield (each step must form the desired product with >50% yield). Note that these transformations can not occur in a single step using the reactions we have learned. Ph
(E)PhCH=CHPh
HO
OH
Ph
(Z)PhCH=CHPh
(Meso) 7) Draw the major organic product(s) of the reaction between trans-­‐3-­‐hexene and bromine in carbontetrachloride as solvent. a) Draw the product in Fischer projection. b) Tell if the product is produced as i) A single stereoisomer ii) A racemic mixture of two enantiomers iii) An equal mixture of two diastereomers iv) An equal mixture of four diastereomers v) An unequal mixture of two diastereomers vi) An unequal mixture of two enantiomers vii) A single Achiral compound 8) Draw the major organic product of eacb of the following chemical reactions: Br
1. KOC(CH 3) 3
2. HCl
a.
HBr
b.
c.
d.
Cl
O
S O
O
2.OsO4 then NaHSO 3
e.
Br
H
f.
1. KOC(CH 3) 3 , HOC(CH 3) 3
1. NaOEt, EtOH, 70 °C
2a. O3, CH2Cl2, -78 °C
2b. DMS