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Topic: 3-phenylpropanal  (Read 37409 times)

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GCT

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3-phenylpropanal
« on: April 30, 2005, 09:29:15 PM »
This problem is somewhat related to a recent question we had in the organic chemistry forum.  

Does anyone here know how one would synthesize 3-phenylpropanal from bromobenzene in three steps?

How about 3-phenylpropanol?

I vaguely recall a clever method used to accomplish this task, although this can certainly be my imagination.
« Last Edit: April 30, 2005, 09:30:53 PM by GCT »

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Re:3-phenylpropanal
« Reply #1 on: May 01, 2005, 02:30:51 AM »
Here is the link to the thread in the organic forum.  In that question, I think the starting material was benzyl bromide, not bromobenzene.

http://www.chemicalforums.com/index.php?board=3;action=display;threadid=3006

Starting from bromobenzene would also be possible in three steps for either the alcohol or the aldehyde.

GCT, if you want I can IM you my idea, I don't want to post it since I think it's a good problem for the non-staff people to ponder.

GCT

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Re:3-phenylpropanal
« Reply #2 on: May 03, 2005, 10:55:02 AM »
I've never "IM" before, although I'm thinking about starting soon.  For now, can you send the proposal through private messaging?  Thanks.

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Re:3-phenylpropanal
« Reply #3 on: May 03, 2005, 04:22:33 PM »
Heh, that's actually what I meant by IM.

I'll send it now.

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Re:3-phenylpropanal
« Reply #4 on: May 06, 2005, 07:41:18 PM »
i am hardly familiar with organic chemistry nowadays, but i think it involves replacing bromo with a C=C group.
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

786mine

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Re:3-phenylpropanal
« Reply #5 on: May 09, 2005, 02:19:01 AM »
can someone write the structure oF 3-phenylpropanal ?

Offline Donaldson Tan

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Re:3-phenylpropanal
« Reply #6 on: May 09, 2005, 06:44:49 PM »
@-CH2-CH2-CH=O

where @ represents the benzene ring
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

KC

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Re:3-phenylpropanal
« Reply #7 on: May 24, 2005, 11:11:57 PM »
Br-benzene +Mg+ Br-allyl
BH3/HOOH/OH
Swern O

KC

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Re:3-phenylpropanal
« Reply #8 on: May 31, 2005, 10:37:17 PM »
wow. this thread is jumpin!!!!
a week, and still not one post?? :(

KC

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Re:3-phenylpropanal
« Reply #9 on: May 31, 2005, 10:46:52 PM »
Alright!!!Next question of the day ??? ???
go from 3-methoxybenzaldehyde to 3-hydroxyphenylacetaldehyde  in TWO steps!!!!


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Re:3-phenylpropanal
« Reply #10 on: June 01, 2005, 06:00:43 PM »
Heh, that one is a lot tougher than the original question.

Doable, but a lot more difficult!
« Last Edit: June 01, 2005, 06:01:00 PM by movies »

Grafter

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Re:3-phenylpropanal
« Reply #11 on: June 01, 2005, 07:25:02 PM »
Incidentally, how do you turn an ether into an alcohol?

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Re:3-phenylpropanal
« Reply #12 on: June 01, 2005, 11:15:59 PM »
Incidentally, how do you turn an ether into an alcohol?

It's usually quite difficult, but in the case of aryl-alkyl ethers it's much easier.  There are several common reagents for this process, the key to this problem is knowing which precise one you need to save yourself a step!

KC

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Re:3-phenylpropanal
« Reply #13 on: June 05, 2005, 09:39:58 PM »
for aryl ethers, simple koh followed by methyl iodide (or eq)...or dimtheyl sulfate (or equiv) could be used.

for alkyl ethers, use williamson ether synth.

KC

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Re:3-phenylpropanal
« Reply #14 on: June 05, 2005, 09:49:11 PM »
 :D Alright!!
It's time for the answer to the first question of the day (since we didn't get any guesses?)  
1. we first need to do a wittig reaction with the aldehyde.  adding the Levine Wittig reagent (triphenylphosphoniummethoxymethyl bromide)...
we have thus formed our new double bond... :)
but this, my friends, is no ordinary double bond...
What we have is a vinyl ether ;D
2. If we hydrolyze the vinyl ether with something strong enough to simultaneously deprotect the aryl ether, we have our product!!!  (remember, vinyl ethers are really just aldehydes or ketons in disguise!!)   A reagent that will affect this elegant transformation would be HBr/acetic acid.

Time for a new question...COME ON...easy or difficult, someone post a question

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