1. Controlled Palladium(0)-Catalyzed Cross-Coupling Polymerizations
Qiao-Sheng Hu, Department of Chemistry, College of Staten Island-City University
of New York, Staten Island, NY 10314
Controlled Pd-catalyzed cross-coupling polymerizations, which could generate conjugated polymers
with controlled length, may have potential applications in fields such as molecular electronics. Based
on the preliminary study of cross-coupling reactions of dihalobenzenes with arylboronic acids on
“Preferential Oxidative Addition”, which it is believed to be the key to realize controlled Pd-catalyzed
cross-coupling polymerizations, we explored Pd-catalyzed reactions of dihalobenzenes with Grignard
reagents including 2,6-dimethylphenylmagnesium bromides. We found with ligands such as
phosphines, the reaction proceed via “Preferential Oxidative Addition” mechanism. The reaction
proceeded via benzyne intermediates with Pd catalysts such as Pd(OAc)2 to give substituted fluorenes.
We have successfully extended the benzyne intermediate hypothesis to the reaction of internal alkynes
with 2,6-dimethylphenylmagnesium bromides and two types of organic compounds, substituted indenes
and (Z)-tetra substituted ethenes, were efficiently obtained. We have also tested Pd/t-Bu3P-catalyzed
Suzuki cross-coupling polymerization of a fluorene-containing monomer and promising result has been
obtained.