[ksr985]

To make a tertiary alcohol using RMgX, can we use an acid chloride insted of an ester? It seems to work out. I have done the ester reaction in the lab. Which will give a higher yield?

[Grafter]

You could, but doesnt it seem a bit like overkill? An ester is perfectly adequate for the job. As the addition of a grignard to a carbonyl is essentially irreversible, the way to get a better yield is to perform the reaction for longer, use a better solvent or less hindered R group. I dont see that using an acid chloride would have any effect on the position of equilibrium.

[movies]

Well, in principle acid chlorides are more reactive and Cl- is a better leaving group than RO-, so it might be a faster reaction.  However, faster is not always better.  Also you have to consider the difficulty with handling an acid chloride.  Esters are pretty robust when it comes to handling in the air and on the bench top, acid chlorides, not so much.

If I had to do it, I would use an ester.