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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Rutherford on January 21, 2013, 10:46:22 AM

Title: Malonate cyclic compound synthesis
Post by: Rutherford on January 21, 2013, 10:46:22 AM

Could someone rationalize the first step in this synthesis? What is happening there?

Title: Re: Malonate cyclic compound synthesis
Post by: discodermolide on January 21, 2013, 10:47:55 AM

The first step is a simple dialkylation of the malonate ester with methyl iodide.

Title: Re: Malonate cyclic compound synthesis
Post by: Rutherford on January 21, 2013, 10:49:53 AM

How does it work?

Title: Re: Malonate cyclic compound synthesis
Post by: discodermolide on January 21, 2013, 10:57:57 AM

The base, NaOEt removes one of the acidic protons of the CH₂ group. They are very acidic due to the electron withdrawing esters. The resulting anion is stabilised by resonance through the ester carbonyls.
Methyl iodide is the electrophile and is attacked by the carbanion to give the methylated compound.
Rinse and repeat for the remaining CH to give the dialkylated compound.

Title: Re: Malonate cyclic compound synthesis
Post by: Rutherford on January 21, 2013, 11:04:34 AM

And the last step is the same process then. Thanks.

Title: Re: Malonate cyclic compound synthesis
Post by: discodermolide on January 21, 2013, 11:07:24 AM

No problem.