[physstudent1]

<img src="http://img503.imageshack.us/img503/7051/norxnqk7.jpg">

the answer is no net reaction but I don't understand why the product isn't the same with a 1-methyl-1-propyl attached to the ring where the carbonyl was? 

[macman104]

Are there any protons on there that are acidic, and may react with the grignard before it gets to attack the ketone?

[physstudent1]

the alcohol proton is slightly acidic so this would react with the grignard ?  but wouldn't that mean it would undergo the reaction of the alcohol's proton reacting with the gringard ?  I'm a little confused on what actually happens when gringards react with protons I just know that you are supposed to keep gringards away from protons

[Gregorian]

You have the right answer. The Hydrogen on the OH group is pretty acidic and Gringard is a very strong base. base + acid = water + salt so now gringard cannot be used to react with the electrophilic carbon of the carbonyl group. That's why there is no reaction

[Gregorian]

actually, my professor said it is not supposed to be a no reaction .. cuz that Hydrogen is not acidic enough!!! so it should react like gringard reacts with ketones forming alcohol

[macman104]

I disagree with your professor.  Grignard reagents are wrecked if there is moisture (aka water), and the proton on the phenol is even more acidic than water.

As far as what happens, a grignard like CH3MgBr, is essentially a delivery of CH3^-.  So, it grabs a proton and you effectively get CH4.  I'm not 100% sure if that's exactly your products, but conceptually, that's why you can't use grignard reagents on compounds with acidic protons.

[bicycle2007]

I think in this case, Grignard agent react with phenol group to release ethane first. After all hydroxyl groups are eliminated, the excess amount of G agent will react with carbonyl group. It's rather expensive in this way of synthesizing

[macman104]

I'm sorry that really doesn't make much sense.  I mean, sure if you add enough, you might react eventually the ketone, but that isn't the point.  That isn't the main reaction, and should not be considered.