One-Pot Halogen Dance/Negishi Coupling of Dibromothiophenes for Regiocontrolled Synthesis of Multiply Arylated Thiophenes
作者:Kentaro Okano、Kazuhiro Sunahara、Yoshiki Yamane、Yuki Hayashi、Atsunori Mori
DOI:10.1002/chem.201604293
日期:2016.11.7
One‐pot halogen dance/Negishi cross‐coupling of readily available 2,5‐dibromothiophenes is described. A lithium diisopropylamide (LDA)‐mediated halogen dance reaction resulted in the formation of thermodynamically stable α‐lithiodibromothiophenes, which were transmetalated with ZnCl2 and subjected to Negishi cross‐coupling to provide the corresponding arylated dibromothiophenes in onepot. The resultant
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.