Reactions of Grignard Reagent: 1,2 vs 1,4 addition So I was reading through Grignard reagent and I came across this answer by jerepierre, which mentions:


  In general, Grignard reagents and organolithium reagents add directly to the carbonyl carbon, while organocuprates (organocopper reagents) add to the beta-position of an unsaturated ketone.


Now, I want to know, what is the meaning of 'in general'? Can anyone please provide me some cases where the general rules are not followed.

Also, I came to know that:



give 1,4 addition with $\ce{PhMgBr}$ to give:



(that reference is difficult to provide at the moment).

Can someone please explain why this happened?
This is not a 1,4 addition.  It is a 1,2 addition across a carbon-carbon double bond.  This mode of reaction is unusual for Grignard reagents, but here a highly stabilized "double benzylic" anion is formed and the competitive reaction of adding to the carbonyl group is sterically hindered.