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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: ExquisiteOwl on May 08, 2018, 10:48:31 AM

Title: Organometallic palladium catalytic cycle
Post by: ExquisiteOwl on May 08, 2018, 10:48:31 AM

Hi guys,

I'm trying to work out the mechanism of this reaction but can't seem to get past the first step. It's mainly the 2 acetate groups attached to the catalyst that are confusing me. I can't figure out if they fall off at the start of the catalytic cycle to give Pd(0) or if they remain intact and are used in the reaction. I've found a similar mechanism online where the catalyst used lacks the 2 acetate groups.

Would really appreciate any help.

Title: Re: Organometallic palladium catalytic cycle
Post by: phth on May 10, 2018, 01:12:04 AM

i They do play a role in the reaction because they can deprotonate palladium hydrido species, for example. But Pd(OAc)2 would probably perform the same as PdCl2. It's just a starting material, and they meant we added a ligand+Pd(OAc)2 as a solution or solids. It's the precatalyst.

Title: Re: Organometallic palladium catalytic cycle
Post by: rolnor on May 10, 2018, 05:07:09 AM

Does not CO reduce Pd(2) to Pd(0)?

Title: Re: Organometallic palladium catalytic cycle
Post by: ExquisiteOwl on May 10, 2018, 08:29:05 AM

Thanks for the replies. I've figured out that the OAc groups fall off and the reaction does proceed via the mechanism I posted. I read a paper that stated that the reaction mainly occurred through the [Pd]-H pathway, rather than the [Pd]-OMe. Does anyone have any clue as to how the active catalyst ([Pd]-H) is generated? I was thinking that maybe an oxidative addition reaction occurred with methanol at the methyl group C-H bond, but I'm not sure if this is possible.