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Topic: Synthesis rxn questions  (Read 5617 times)

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untitled

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Synthesis rxn questions
« on: April 13, 2006, 08:44:19 AM »
Hi,

There are 3 synthesis reactions that I'm stuck with. What's in black is the question
(reaction-->product) and what's in red is what I've tried doing. Can anyone help me with them to know what's right and what's wrong? Thank you!

Offline AWK

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Re: Synthesis rxn questions
« Reply #1 on: April 13, 2006, 08:53:27 AM »
Reaction 1 is reliable, though there is a printing error, and something more is needed
Raction 2 is unreliable.
The last step of reaction 3 is wrong
« Last Edit: April 13, 2006, 08:57:55 AM by AWK »
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Offline Albert

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Re: Synthesis rxn questions
« Reply #2 on: April 13, 2006, 09:00:33 AM »
What about using NaH in the second reaction?

untitled

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Re: Synthesis rxn questions
« Reply #3 on: April 13, 2006, 09:02:09 AM »
How would NaH lead to the product? You still need something no?

Offline AWK

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Re: Synthesis rxn questions
« Reply #4 on: April 13, 2006, 09:44:13 AM »
Reaction 1 produces CH2=C6H10. You should isomerize this compound to 1-methyl-1-cyclohexene (by thermal or chemical way)
In reaction 2 , NaOH cause elimination, in this case rather to CH2=C5H8. Anti-Markovnikow addition of BH3 and oxidation can produce needed alcohol
In reaction 3, step 2, elimination of HBr produces CH2=C5H8, then oxidation of double bond gives diol
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Offline Albert

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Re: Synthesis rxn questions
« Reply #5 on: April 13, 2006, 05:31:10 PM »
In reaction 3, step 2, elimination of HBr produces CH2=C5H8, then oxidation of double bond gives diol

Yes, exactly. I'd carry out the former with (CH3)3COK and (CH3)3COH (according to Hofmann's Rule) and the latter using KMnO4 (0°C, pH = 7) or OsO4 (if you like expensive things  8) ).

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