Biphenyl Birch reduction

The Birch reduction of benzoic acid is the same type as that of biphenyl, and the product, with protonation successively at C-4 and C-l is the acid 7.102. In the reaction medium, it will be benzoate ion 7.101 that is being reduced. As a result of the delocalisation of the negative charge in the benzoate ion, we should probably regard the carboxylate ion more as a C- than as a Z-substituent. 

---