Programmed Synthesis of Tetraarylthiophenes through Sequential C−H Arylation
摘要:
A general protocol for the programmed synthesis of tetraarylthiophenes has been established. The utilization of three catalysts, RhCl(CO){P[OCH(CF3)(2)](3)}(2), PdCl2/P[OCH(CF3)(2)](3), and PdCl2/bipy, enables regioselective sequential arylations at the three C-H bonds of 3-methoxythiophene with iodoarenes. Interesting metal- and ligand-controlled regiodivergent: C-H arylations have been uncovered during this study. The installation of fourth aryl groups to the thus-generated 2,4,5-triaryl-3-methoxythiophenes has been accomplished through a sequence of demethylation, triflation, and Suzuki-Miyaura coupling.