organic chemistry - Synthesis of Haloperidol with 4-chlorobutanoyl chloride and piperidin-4-one

I searched for a easy synthesis on Haloperidol.

Step 1 and 2 are taken from https://www.slideshare.net/SagarJoshi2/antipsychotics-33785528 (Slide 23). I just tried to work out a way to prepare 4-(4-chlorophenyl)piperidin-4-ol via Grignard.

Does the 4-chloro group has any negative influence on the reaction.

Answer

The reaction mechanism for the step in question simply involves initial formation of a Grignard reagent followed by nucleophilic attack into the ketone.

When forming Grignard reagents from halides, there is a general trend that the rates of formation are in the order I > Br >> Cl, making it possible to get selectivity where multiple halides exist.