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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: neobenzene on February 08, 2013, 11:59:25 PM

Title: Williamson Ether Synthesis
Post by: neobenzene on February 08, 2013, 11:59:25 PM
Hi...I've been recently taught that in the Williamson ether synthesis, the halide to be reacted, should be a primary halide. This is because if the halide is secondary or tertiary, due to greater sterric crowding, elimination dominates over substitution, and an alkene is formed.

Now, what if the halide I'm using is benzyl chloride....benzene ring with a -CH2Cl attached to it. I'm  not sure how to draw it using the SMILES engine.

Anyways, my question is, if we use benzyl chloride, and any sodium alkoxide (RONa), what will the product be? Will it be an ether, since the halide is primary, or will it be an alkene, since the halide has a bulky benzene ring?

Thanks!
Title: Re: Williamson Ether Synthesis
Post by: discodermolide on February 09, 2013, 02:10:28 AM
Benzyl chloride cannot form an alkene. So you will form the ether.
ClCC1=CC=CC=C1
Title: Re: Williamson Ether Synthesis
Post by: neobenzene on February 09, 2013, 03:22:45 AM
Why can't it form an alkene?
Title: Re: Williamson Ether Synthesis
Post by: discodermolide on February 09, 2013, 03:36:23 AM
Because there is no proton to initiate the elimination.
You cannot break the aromaticity.
You will not get
C=C1=CC=CC=C1
or
C=C1C=CC=CC1
or
C=C1C=CCC=C1

The first molecule does not make any sense.
Title: Re: Williamson Ether Synthesis
Post by: neobenzene on February 09, 2013, 05:20:43 AM
Thanks!!