Chemistry 6372
Fall 2002
Homework #7
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Name
Points:!!
1 / 30 /
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2 / 20 /
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3 / 15 /
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4 / 15 /
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5 / 10 /
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6 / 10 /
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Total:!!
100 points /
Summary of points of all homework sets: 700/
The homework set is OFFICIALLY due next Wednesday (27th ) at 4pm (to
hand in in person or to put it into my mail box). However, NO points for late
submission will be deducted if you hand in the homework set before
December 2nd 9 a.m. in class.
1) Answer the following questions from our book: Chapter 12,
question 1 a, b, c, e, g, i, and j.
This question was on last years final!
2) For each of the following molecules (a-d), give the valence electron count, the formal
oxidation state of the metal(s), and the corresponding d electron count.
(a)
CH3
Ta
CH2
(b)
CO
CO
Ru
OC
Ru
OC
(c)
OC
OC
CO
CO
Co
CO
Co
OC
CO
OC
Co
Co
OC
CO
CO
CO
(d)
Fe
This question was on last years final!
3) Propose a mechanism for the following transformation and classify the reaction(s) in
terms we discussed in class:
OH
O
H3 C
H3 C
CH3
1. Heat (200C)
2. H2/ Pt
CHCH3
CH3
4) All cis-cyclononatetraene undergoes a spontaneous electrocyclic
ring closure at 25C to afford a single product. Suggest a structure for
this product. Also, describe an alternative symmetry-allowed
electrocyclic reaction that would lead to an isomeric
bicyclononatriene. Explain why the product of this alternative reaction
pathway is NOT formed.
5) Both, 2-acetoxy-trans-3-heptene and 4-acetoxy-trans-2-heptene
were found to give similar mixtures of 1,3-heptadiene and 2,4
heptadiene upon gas pyrolysis at 350C. Furthermore, examination of
recovered SM revealed it to consist of a mixture of 60% of the 2acetoxy compound and 40% of the 4-acetoxy compound, no matter
which one had been the reactant. Explain.
6) Predict which is the more likely mode of ring closure for oxonin:
a) Cyclization of the tetraene unit to a bicyclo[6.1.0]system, or
b) Cycization of a triene unit to a bicyclo[4.3.0]system.
O
Oxonin