Chem210-1 F08 Ex3 p01a

Chem210-1 F08 Ex3 p01a - cis-cyclooctene, a n d provide the...

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1. The compounds cis -cyclooctene and trans -cyclooctene are shown on the right; each is represented by both a "standard" Lewis structure and by a structure which suggests 3-D geometry o r o r cis = trans = a) answer the following questions about each of these forms of cyclooctene (2 pts each) i) does the cis compound have any chiral carbons? ___ NO ___ does the trans ? __ NO __ ii) does the cis compound have a plane of symmetry? __ YES __ does the trans ? ___ NO ___ iii) does the cis compound come as a pair of enantiomers? ___ NO ___ does the trans ? __ YES __ 2. Which of the two geometric isomers - the cis -cyclooctene or the trans -cyclooctene - would be expected to have the more negative heat of hydrogenation? Why? (6 points) 3. O t h e r t h a n the alkyne cyclooctyne , propose t w o eight carbon compounds that you could use as precursors to form
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Unformatted text preview: cis-cyclooctene, a n d provide the reactants (and conditions) that could be used to bring about the transformation. (4 pts each, 8 pts for the entire question) (reactant 1) (reactant 2) (reagents 1) (reagents 2) t r a n s : more negative heat of hydrogenation => less stable; remember, trans double bonds are imcopatable with the lower rings systems, and even if you get up to eight carbons a trans double bond still introduces significatn ring strain, coupled with some steric strain associated with the positions of some of the hydrogens in the contorted ring structure required Br conc. EtONa / EtOH; ( / / 29 2 4 /...
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This note was uploaded on 02/28/2012 for the course CHEM 210-1 taught by Professor Trzupek during the Fall '08 term at Northwestern.

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