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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: shrikantvarma on January 03, 2011, 09:32:10 AM

Title: How to convert ester to ketone??
Post by: shrikantvarma on January 03, 2011, 09:32:10 AM: How to convert ester to ketone?? is there any name reaction or any synthetic transformation pls. help??
Title: Re: How to convert ester to ketone??
Post by: discodermolide on January 03, 2011, 10:01:21 AM: Quote from: shrikantvarma on January 03, 2011, 09:32:10 AM
How to convert ester to ketone?? is there any name reaction or any synthetic transformation pls. help??

Use a Grignard reagent, look at some of Paterson's chemistry on discodermolide
Title: Re: How to convert ester to ketone??
Post by: shrikantvarma on January 03, 2011, 10:14:30 AM: Quote from: discodermolide on January 03, 2011, 10:01:21 AM
Quote from: shrikantvarma on January 03, 2011, 09:32:10 AM
How to convert ester to ketone?? is there any name reaction or any synthetic transformation pls. help??

Use a Grignard reagent, look at some of Paterson's chemistry on discodermolide

i am not getting exact synthesis can u explain ??

thanks
Title: Re: How to convert ester to ketone??
Post by: tupamato on January 03, 2011, 12:15:26 PM: (https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fimg577.imageshack.us%2Fimg577%2F5342%2Fp1010836h.jpg&hash=fd1ecb6c4755600ff97496a962eb9caf4877f503)
Sn-Ac
the intermediate ketone reacts with a second molecule of grignard to form alcohols
Title: Re: How to convert ester to ketone??
Post by: chronictonic on January 04, 2011, 12:33:52 AM: Ok, try this. It's a bit long winded but;

1- hydrolyse the ester to and acid
2- derivatise the acid to and acyl chloride with thionyl chloride
3- attck the carbonyl with aziridine to form N-acetyl aziridine
4- react the alkyl lithium group you want for the other side of your ketone (in theory the grinard would work here too)
and voila! done. No tertiary alcohol in sight.

OR perhaps you could reduce your ester to and aldehyde and then just use the grinard. With no leaving group (H is a terrible leaving group) that should afford you a secondary alcohol that you could re oxidise to the desired ketone.

depends on your substrate
Title: Re: How to convert ester to ketone??
Post by: g-bones on January 04, 2011, 03:36:42 PM: Quote from: chronictonic on January 04, 2011, 12:33:52 AM
Ok, try this. It's a bit long winded but;

1- hydrolyse the ester to and acid
2- derivatise the acid to and acyl chloride with thionyl chloride
3- attck the carbonyl with aziridine to form N-acetyl aziridine
4- react the alkyl lithium group you want for the other side of your ketone (in theory the grinard would work here too)
and voila! done. No tertiary alcohol in sight.

OR perhaps you could reduce your ester to and aldehyde and then just use the grinard. With no leaving group (H is a terrible leaving group) that should afford you a secondary alcohol that you could re oxidise to the desired ketone.

depends on your substrate

I would go with reduction of the ester to an aldehyde (DIBAL-H) then grignard than oxidize, or form the weinreb amide and attack with organometallic reagent.
Title: Re: How to convert ester to ketone??
Post by: science123 on January 04, 2011, 05:42:27 PM: Hydrolyze to carboxylic acid
React with 2 equivalents of alkyl lithium followed by H3O+ workup
Title: Re: How to convert ester to ketone??
Post by: cleopas on April 19, 2012, 09:41:20 AM: Quote from: shrikantvarma on January 03, 2011, 09:32:10 AM
How to convert ester to ketone?? is there any name reaction or any synthetic transformation pls. help??

the the ketone do some idoformation on it then tale that iodoform treat it with stong base OH then will get your carboxylic acid with CI4 as by product then just react then carboxylic acid with alcohol.