Download Exam II Questions with Answers - Organic Chemistry 1 | CHEM 3351 and more Exams Biochemistry in PDF only on Docsity! Chemistry 3351-100
Organic Chemistry /Dr. Barney Ellison
Thursday: Oct. 25" @ 7:00pm — 9:00/2"* Exam/Hellems 252
Name: a s (please print)
1. (20 pts) For each of the following compounds, assign R or S the each
stereocenter.
ce @)
ae @
a) ny
b)
Ce ()
© o
¢)
3.(10 pts) In the formation of Grignard reagents from Mg and alkyl
halides, the most frequent side reactions are dimerization and
disproportionation, as in the following example. Propose a mechanism for
these side reactions.
ce MgCe
Mg
Sao + +
ether solvent
a) Ce
a a7, es
Dl gee Oe
Abd Y
cr Or &
eee ST Ty Matt 04
Sp \eadenze C Dene ae Gorm , Bu ete
Caw Uw rr.
oN ‘ av Abnet .
CX i e
Le - i —=> eg io
n
A H I
Lo) 2 en
4. (10 pts) Explain the following observations.
a) (S)-3-bromo-3-methylhexane reacts in aqueous acetone to give
racemic 3-methyl-3-hexanol.
Br. CH; HO CH,
H,O/acetone
(S) —_— ($) we Ce
a
top
a — 5 Msi
= \\, 0:
ee ee ae a
KK ho 30% Su ‘oO
ere
b) — (R)-2-bromo-2,4-dimethylhexane reacts in aqueous acetone to give
optically active 2,4-dimethyl-2-hexanol.
Anfet: fe
j
, <
on be : ik Chg —
| a7 ey = A qr ar
uth ra Ch,Ch, 5
| Bo
VA
| » Ns
o> os
cH
Cech, R
Crivd Coal nawod pace
-10-
7. (20 pts) In each of the following pairs of reactions, predict which one is
faster and explain why.
a) (CH,),CHCH,Cé + N;~ (EtOH solvent) = (CH;);CHCH,N,; + Cé-
han (CH,),CHCH,I + N,~ (EtOH solvent) > (CH,),CHCH,N, +I-
oe)
Ton a eRta Lemdg garg thn
b) (CH,),CBr + H,O +A— (CH,),COH+HBr <= Cab,
(CH,),CHBr + H,O +A-> (CH,),CHOH + HBr
a oan Sy A Yxus,
uly
CK— ot, Sa \rgvek AAR oa
&
2?
: wh"
“\
«Ch
Ch eZ
9) pda Vindoad
ea CH,SH
+ SH7 a
od + Bro
Ng ga Sue NSB
Gs ie ok ee eee
d) CH,CH,Br + CN~ [CH,OH solvent] = CH,CH,CN + Br-
CH,CH,Br + CN~ [(CH,);NCHO solvent] > CH,CH,CN + Br-
& DMF Atadlin Lf
_ eR oe I). bred Chon
ek S veer eeuperd
©
SO thy 1
