Grignards and carboxylic acids?

[johnwandering]

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I know that grigs can create carboxylic acids (grig +CO2)

But i was wondering what happens when it encounters a CA. Does it create a geminal diol? Or just snatch the H and become protonated?

 

[johnwandering]

Also, for grigs +esters
Why does grig knock off OR- but not the final OH-? I thought OR- had a much lower Pkb number than OH-

 

[dmf2682]

the grignard makes a carboxylate in the first step, which is then protonated by acid in the second step. Second step only occurs after the grignard reagent is out of the picture.

 

[hellocubed]

So, just like an amine attacking the carboxylic acid,

Grignard just takes the H off the Carboxylic acid...

 

[gettheleadout]

So, just like an amine attacking the carboxylic acid,

Grignard just takes the H off the Carboxylic acid...

Which makes sense considering Grignards are basic enough to deprotonate alcohols.