1. Synthesis of Indole Oligomers Via Iterative Suzuki Couplings
Jason M. Belitsky Department of Chemistry and Biochemistry, Oberlin College, Oberlin OH, 44074
Eumelanin, the black to brown human pigment, is composed of dihydroxyindole oligomers of which the structure above on the right is representative. In order to approach such structures, methods for the synthesis of indole oligomers are being developed. In the course of this work, a Pd-catalyzed homocoupling reaction of indole and aryl boronic acids has been optimized. The reaction is operationally simple (air, water, room temperature), and will be incorporated into iterative Suzuki coupling routes to (dihydroxy)indole oligomers.
Pd(OAc)2 (5 mol %)
TsCl (50 mol %)
Na2CO3, H2O/acetone,
room temp, 2 hrs
81 %