Microwave-promoted and chelation-controlled double arylations of terminal olefinic carbon of vinyl ethers.
Herein we report a rapid, palladium-catalyzed terminal diarylation of the chelating olefin N,N-dimethyl(2-ethenyloxy)ethanamine under noninert conditions utilizing controlled microwave heating as a convenient energy source. Among the aryl bromides examined, both electron-rich and electron-poor substrates were demonstrated to furnish useful yields after only 10-120 min of directed microwave heating at 160-200 degrees C. The good terminal regioselectivity suggests that the precatalyst (Herrmann's palladacycle) serves as a source of weakly coordinated palladium(0) in the investigated high-temperature Heck process.
Svennebring
Andreas
A
Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala Biomedical Centre, Uppsala University, Box 574, SE-751 23 Uppsala, Sweden.
Nilsson
Peter
P
Larhed
Mats
M