[cseil]

I'm having problems with this synthesis.

I really have no idea how to replace OH with CH3OH 

[kriggy]

Your suggestion will probably not work: its nucleophilic substitution and while Cl^- can be substitued it requires electron withdrawing group while you have electron donating group (OH). You probably dont want to add methoxy group in the way you suggest.

Maybe Sandmeyer reaction could work. Dakin reaction seems even better. Try to figure it out

edit: well depends on what structure you want? the one named in the topic name or the one you drew. My suggetion should work for the 2nd case

[Babcock_Hall]

Your name and the final structure in your diagram do not match.  4-methoxyphenylmethanol would be CH₃O-Ar-CH₂OH, with the two substituents having a para relationship.

[cseil]

Sorry, I know, I drew only the steps I could do!

[Babcock_Hall]

I don't think your strategy is optimal.  I would work the problem backward (retrosynthetic analysis), but this is not absolutely necessary.  There is a pretty straightforward route that does not involve having to replace the -OH with -CH₂OH.

[cseil]

I believe I have to study other reaction mechanism because with what I know I can't find a solution.
The problem is my organic chemistry 1 doesn't comprehend everything about aromatic compounds and sometimes I want to synthetise compounds and I can't.

I'll try to figure it out tomorrow and search for Dakin and Sandmeyer reactions,
thank you

[Babcock_Hall]

I'll give you a hint as a freebie.  It is easy to envision a precursor to the methoxyl group (CH₃O-), namely the hydroxyl group (how would you do this?).  Therefore, all you have to do is to put the appropriate group onto the position that is para to this group.  Have you studied electrophilic aromatic substitution reactions?