Process for preparation of biphenyl derivatives

摘要

A process is described for preparing a compound of the formula I: <IMAGE> (I) or a salt thereof; wherein X is a protecting group and R1, R2, R3 and R4 are each independently hydrogen, C1-6 alkyl or C1-6 perfluoroalkyl, R5 is hydrogen or when n is 1 R5 taken together with R3 comprises a double bond; m is 1, 2 or 3; n is 0 or 1, and p is 0, 1 or 2.