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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: OrganicDan96 on June 01, 2018, 01:34:19 PM

Title: Cleavage of benzylthioether.
Post by: OrganicDan96 on June 01, 2018, 01:34:19 PM

I want to cleave a benzylthioether to give a thiol, the most common conditions for this is by sodium in ammonia however the molecule contains an fmoc protected amine and this would probably be removed under these conditions. I know that you cannot use Pd/C H2 like for benzylethers as the the sulphur poisons the catalyst, so I am looking for relatively mild conditions for this transfomation. does anyone know of such conditions?

Title: Re: Cleavage of benzylthioether.
Post by: phth on June 02, 2018, 07:01:32 PM

I think your best bet it to go the oxidative method: you oxidize the thioether and benzyl cation will fall off forming a disulfide. I wouldn't bet on there not being a set of hydrogenation conditions that will work, also...

http://pubs.rsc.org/en/Content/ArticleLanding/1991/C3/C39910000167#!divAbstract

Title: Re: Cleavage of benzylthioether.
Post by: OrganicDan96 on June 07, 2018, 03:35:58 PM

Thanks, after that oxidation wouldn't i need to cleave the disulfide to get back to the thiol?

Title: Re: Cleavage of benzylthioether.
Post by: wildfyr on June 07, 2018, 03:38:20 PM

Yes, but a mild reagent like DTT should do the job without touching anything else.

Title: Re: Cleavage of benzylthioether.
Post by: OrganicDan96 on June 08, 2018, 01:27:39 PM

i hove found a method that uses zinc and ammonium formate, does this seem like a viable option?

Title: Re: Cleavage of benzylthioether.
Post by: wildfyr on June 08, 2018, 01:55:16 PM

Depends on the rest of your molecule, but on its face, whatever works.