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Topic: synthesis problems  (Read 5043 times)

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synthesis87

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synthesis problems
« on: April 15, 2006, 10:03:51 PM »
Alright, so I have a cyclohexane, and I'm trying to synthesize several different things... First of all, how would I synthesize (from a cyclohexane) this:

cyclohexane-C~C-cyclohexane
(where ~ is a triple bond, - is single bond)

what I tried to do was... for two equivalents of cyclohexene (which i formed by radical bromination and dehydrohalogenation), add one equivalent of H-C~C-H... would that join the two cyclohexenes the way I want them to??  ???

Secondly, to form this:

CH3-C~C-cyclohexane

Can you do this?

HC~CH -------(1. NaNH2, NH3; 2. CH3Br)---->CH3C~CH ------(1. NaNH2, NH3; 2. bromocyclohexane)------> CH3-C~C-cyclohexane
[where bromocyclohexane is formed by radical bromination of the starting material... am I allowed to add my starting material this late in a synthesis problem?]

Lastly... I have to synthesize this 2 ringed structure that I do not know how to name... but I'll try to describe it...

on a cyclohexene (double bond between C1 and C2) with a 2 carbon bridge connecting C3 and C6, there's [CO2CH3] group attached on C4

To synthesize that from cyclohexane... can I do....

form cyclohexene... halogenate to form 1,2-dibromocyclohexane... add NaH and 2-propanol to form 1,3-cyclohexadiene... add H-C~C-CO2CH3 [which i dont know if it's a valid reagent or not]... halogenate... and will I end up with the desired product?


Any help would be appreciated  :-[

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Re: synthesis problems
« Reply #1 on: April 16, 2006, 12:54:10 PM »
The first two sound good to me.  Nice work!

Make sure you have a base in the first one, the synthesis would be that same as you wrote for the second problem, but you would use bromocyclohexane twice.

One thing on the third one:
The dienophile you want to use in the third one is called methyl propiolate.  It's commercially available, so it's a valid reagent, but it would give you two double bonds in the product.  I think you want to use methyl acrylate where you have a double bond instead of a triple bond.
« Last Edit: April 16, 2006, 12:58:05 PM by movies »

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