Integration of Pd and Cu on polymer: a powerful bimetallic heterogeneous catalyst for sequential synthesis of quinoxalines

摘要

Pd2+/Cu2+ bimetallic catalysts immobilized on ethylenediamine-functionalized poly(vinyl chloride) (Pd-II/Cu-II@EDA-PVC) were developed by combining two metallic catalysts that complement rather than inhibit one another. The synthesized Pd-II/Cu-II@EDA-PVC were screened for their catalytic activity and found to be excellent in the one-pot sequential synthesis of quinoxalines from 1,2-diphenylacetylenes and o-phenylenediamines. Both Pd2+ and Cu2+ are indispensable and play crucial roles in this transformation. This one-pot sequential reaction proceeds well and tolerates various available substrates to form the desired product in excellent yield. A plausible mechanism was proposed for this conversion.