[ch3mq]

So I understand that if a grignard reagent mixes with a carboxylic acid, you pretty much kill off the grignard due to the proton from the acid.  But I can't seem to put a finger on why this same thing wont happen to lithium aluminum hydride.  Some enlightenment please?  I'm sure it's some really simple thing that I'm overlooking or forgot about.

[Dan]

The same thing willl happen, 0.25 equivalents of LAH (ie 1 eq of hydride) will be consumed in deprotonation of the acid. The point is that LAH will still react with the aluminium carboxylate,
                                                                 
RCOOH ---> RCOOAl^-H₃ ---> RCHO^-OAl₂ ---> RCHO --etc.--> RCH₂OH

whereas a grignard will not react with RCOOMgX formed by deprotonation.

[ch3mq]

Thank you for clearing that up.