Sequential Pd(II)-Pd(0) catalysis for the rapid synthesis of coumarins.
Electrophilic palladium-catalyzed cycloisomerization of brominated aryl propiolates produces brominated coumarins. The brominated coumarins can be diversified by reduction of the Pd(II) catalyst to Pd(0) followed by Suzuki, Sonogashira, Heck, or Hartwig-Buchwald coupling. Thus, a single loading of precatalyst can be used to conduct sequential reactions, allowing the synthesis of functionalized coumarins. Extension of this methodology toward the synthesis of coumarin libraries is discussed.
Li
Kelin
K
Department of Chemistry, 1251 Wescoe Hall Drive, 2010 Malott Hall, University of Kansas, Lawrence, Kansas 66045-7582, USA.
Zeng
Yibin
Y
Neuenswander
Ben
B
Tunge
Jon A
JA
D001966:Bromine / Q000737:chemistry; D002384:Catalysis; D003374:Coumarins / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*
D003374:Coumarins; D010165:Palladium; D001966:Bromine