233, CHEM Fall 2008
Midterm #3
Ian R. Gould
PRINTED FIRST NAME
PRINTED LAST NAME
ASU ID or Posting ID
Person on your LEFT (or Aisle)
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Person on your RIGHT (or Aisle)
1_____________/14 ........ 2_____________/26 ........ 3_____________/32 ........ 4_____________/48 ........ 5_____________/12 ........ 6_____________/18 ........ 7_____________/25 ........ Total (incl Extra)________/175+5
He B C N O S F Cl Ne Ar Kr Xe Rn
Interaction Energies, kcal/mol Eclipsing H/H H/Me Me/Me Me/Et ~1.0 ~1.4 ~2.6 ~2.9 Gauche Me/Me Et/Me i-Pr/Me t-Bu/Me ~0.9 ~0.95 ~1.1 ~2.7
Extra Credit_____/5
H Li Be Na Mg K Ca Sc Ti V Y Cr Mn Fe Co Ni Cu Zn
Al Si P
Ga Ge As Se Br In Sn Sb Te I Tl Pb Bi Po At
Rb Sr Cs Ba
Zr Nb Mo Tc Ru Rh Pd Ag Cd Re Os Ir Pt Au Hg
O H N H C H
3300
Lu Hf Ta W
small range range of values broad peak
C N C O O
Infrared Correlation Chart
usually strong
C H C
16001660
C N
Approximate Coupling Constants, J (Hz), for 1H NMR Spectra
H H C C H H C C H C C H H
C H
3000 3100
H
27202820 2 peaks
O C N C O C
1735 1680
~7
H
N H
broad with spikes ~3300
2200
C O H
broad ~3300
H C
2200
OR O C
1710 1650 1600
~10
~8
H
28502960
CH
~2
H
O C O H
broad ~3000
O C NR2 C C
~2 ~15
H H
(cm-1)
3500
3000
2500
2000
1500
amine R alcohol R
NH2 variable and condition OH dependent, ca. 2 - 6 ! O C H
10 200 9 180
NMR Correlation Charts
OCH2 H2C X
O C CH3 H2C NR2
O R C OH (!, ppm)
11 220 O
Aromatic Ar H mainly 8 - 6.5 C CH2
8 160 7 140 6 120 5 100 4 80
C CH
3 60 2 40
Alkyl 3Y > 2Y > 1Y
1 20 0 0
R C OH
O C
R C N R2C Aromatic CR2 RC
OCH2 CR
Alkyl 3Y > 2Y > 1Y C X
C NR2
CHEMISTRY 233, Fall 2008, MIDTERM 3
-2-
NAME
Question 1 (14 pts.) Give the IUPAC name for the following. Remember to use R/S and E/Z where appropriate.
Br Question 2 (26 pts.) For the following Lewis/Bronsted acid base reactions: 1) add the curved arrow pushing that describes bond breaking/making (if it is helpful, redraw the acid as a Lewis structure and draw all resonance contributors for the cations) 2) indicate which would be the fastest and give a BRIEF explanation for your choice 3) draw a reaction energy diagram to support your conclusion HBr A
HBr B
Extra Credit (5 pts) Compared to saturated fats, unsaturated fats tend to have more: C=C bonds bonds C-H O-H bonds C=O bonds
CHEMISTRY 233, Fall 2008 MIDTERM 3
-3-
NAME
Question 3a (16 pts) COMPLETE the curved arrow-pushing mechanism for the following reaction (the first step is started for you). In your mechanism, include the following: 1) the Lewis acid and base at each step where appropriate, and whether they are also Bronsted acids and bases (including the first step that is started for you) 2) draw all resonance contributors for any intermediates 3) indicate the RATE DETERMINING STEP
H
Br HBr
Br
Question 3b (16 pts) Draw a reaction energy diagram that corresponds to your mechanism. On the diagram, clearly indicate the ACTIVATION ENERGY CORRESPONDING TO YOUR RATE DETERMINING STEP and also the REACTION EXOTHERMOCITY. For your rate determining step ONLY, include a drawing of the transition state and also indicate the position of this transition state on your reaction energy diagram
CHEMISTRY 233, Fall 2008, MIDTERM 3
-4-
NAME
Question 4 (48 pts.) For each of the following reactions, add the missing reactants, reagents/conditions or products as required. clearly indicate relative sterochemistry where relevant
(a)
Br2 MeOH
(b)
OCH3
H2 (c) Pd/C
Ph Me
Ph Me
(d)
NBS h!
(e)
HBr (catalytic) H2O
OH (e)
CHEMISTRY 233, Fall 2008, MIDTERM 3
-5-
NAME
Question 5 (12 pts) The structure of (+)-hydroxycitric acid is shown below. a) What is the configuration (R/S) at the carbon indicated by the arrow in (+)-hydroxycitric acid? _________ b) What would the configuratio...