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Topic: Reagent Problem  (Read 5911 times)

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Offline Dolphinsiu

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Reagent Problem
« on: May 02, 2007, 03:18:24 AM »


The reagent for the first equation is
1. O3
2. Zn/H2O

But do you know what reagent will change into the second equation?
Thank you! (This is past paper question, but I cannot think out of any reagent although it may be taught.)

Offline sjb

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Re: Reagent Problem
« Reply #1 on: May 02, 2007, 06:46:19 AM »
But do you know what reagent will change into the second equation?
Thank you! (This is past paper question, but I cannot think out of any reagent although it may be taught.)

What reactions do you know that will convert two carbonyls to a conjugated enone?

S

Offline Dolphinsiu

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Re: Reagent Problem
« Reply #2 on: May 02, 2007, 01:20:24 PM »
http://en.wikipedia.org/wiki/Knoevenagel_condensation

Is it related to above website?

1. CH2Z2
2 - H2O

am I correct?

Offline refid

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Re: Reagent Problem
« Reply #3 on: May 02, 2007, 01:24:19 PM »
I think this is  a simple adol condensation, deprotonate at an alpha hydrogen, count from enolate to next carbonyl carbon you get your seven&five membered ring

i remember from school these questions were tricky ;)

Offline refid

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Re: Reagent Problem
« Reply #4 on: May 02, 2007, 01:44:11 PM »
intramolecular aldol condensation i beleive is what its called

Offline Dolphinsiu

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Re: Reagent Problem
« Reply #5 on: May 03, 2007, 03:11:23 AM »
o i c!

The reagent can be

1. OH-
2. H+ / -H2O

or

1. H+
2. OH-/ -H2O

but there is 2 carbonyl group! Do adol condensation really work?

Offline refid

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Re: Reagent Problem
« Reply #6 on: May 03, 2007, 12:11:36 PM »
one of the carbonyl's a-carbon would lose an a-hydrogen & form the enolate.... the second carbonyl carbon would serve the enolate attack position


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