preparation of 4-t-butyldiphenol

the following procedure seems to be the easiest.
from a chinese patent. application number:99124902

1. liquifiy pure diphenol by warming. no solvent needed.
2. add 1-5% TsOH-H2O.
3. keep temp at 135C, add 1 eq. MTBE dropwise in 2-3 hr (a cold condenser needed).
4. 1 hr later, you get the title compound with a yield >75%









note:
I tried the reaction, everything worked out as described.

ortho-directed reaction of phenol

1. lewis acid-acid chloride/halides
usually no selectivity, both ortho and para product can be formed.

2 dibalH-ester
ester reduced by dibalH, then Al chelate with the phenol to give only ortho product(diol).

3. phenylboronic acid/aldehyde
boron atom formed bonds with the aldehyde and the phenol. same as dibalH, but gives boron complex, after H2O2 oxidation, gives diol.

4. alcl3/BCl3/cynide
gives phenol ketone after hydrolysis.