The Suzuki–Miyaura Cross-Coupling as the Key Step in the Synthesis of 2-Aminobiphenyls and 2,2'-Diaminobiphenyls: Application in the Synthesis of Schiff Base Complexes of Zn

Abstract

2‐Nitrophenylboronic acids serve as interesting starting materials for the construction of biphenyl‐ and terphenyl‐based amines if subjected to the Suzuki–Miyaura reaction. Unfortunately, these boronic acids suffer from low reactivity in Suzuki reactions, alongside their low stability in the presence of Pd. Herein, a general method for the construction of 2‐nitro‐substituted bi‐ and terphenyls is presented, with special emphasis on the synthesis of 2‐amino‐2'‐nitrobi‐ and terphenyls. Comparisons are made with other boronic acids that have some of the aforementioned issues. Finally, the application of the obtained 2‐amino‐2'‐nitrobi‐ and terphenyls as starting materials for the synthesis of bi‐ and terphenyl based di‐ and triamines is encountered for, with emphasis on the use of these amines as precursors for Schiff base ligands. In addition, the synthesis of some Zn complexes of these ligands is presented.