A convenient and efficient one pot synthesis of unsymmetrically substituted &ITp&IT-terphenyls via a phosphine-free double Suzuki cross-coupling protocol using 1,4-dibromo-2-nitrobenzene as the substrate

作者：Kazi Shahid A; Campi Eva M; Hearn Milton Tw^*

来源：Tetrahedron, 2018, 74(15): 1731-1741.

DOI：10.1016/j.tet.2018.01.031

• Substituted p-terphenyls
• Phosphine-free double Suzuki cross-coupling
• One pot synthesis
• Oxidative additions
• Transmetalations
• Reductive eliminations

A synthetic procedure has been developed to enable the sequential regio-selective Suzuki-Miyaura cross-coupling of 1,4-dibromo-2-nitrobenzene with a variety of arylboronic acids. The first Suzuki coupling step, using a phosphine-free palladium catalyst at room temperature, gave selective coupling at the position ortho to the nitro group, opening a convenient synthetic route to unsymmetrical para-terphenyls. The bromobiaryl product was then subjected directly to the second coupling step, in situ, using preferred aryl-boronic acids to give by this one-pot batch procedure unsymmetrically substituted paraterphenyls in excellent overall isolated yields. This methodology should be particularly suited for the generation of targeted chemical libraries, as well as for the synthesis of precursors of biologically active compounds or natural products which are derived from the unsymmetrical para-terphenyl core.

• 出版日期2018-4-12