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.
less‐reactive β position of thiophenes was previously inaccessible to direct functionalization. However, the β selectivity observed with the catalytic system PdCl2/POCH(CF3)2}3/Ag2CO3 in the arylation of thiophenes with iodoarenes (see scheme) is a remarkably general phenomenon applicable to unsubstituted, monosubstituted, and disubstituted thiophene derivatives, as well as thiophene‐containing fused aromatic
开放获取:通常无法直接将噻吩的反应性降低的噻吩的β位置进行直接功能化。但是,在噻吩与碘代芳烃的芳基化反应中,催化体系PdCl 2 / P OCH(CF 3)2 } 3 / Ag 2 CO 3所观察到的β选择性是一种显着的普遍现象,适用于未取代的,单取代的,和二取代的噻吩衍生物,以及含噻吩的稠合芳族化合物。