Multiple-Functional Diphosphines: Synthesis, Characterization, andApplication to Pd-Catalyzed Alkoxycarbonylation of Alkynes

摘要

A series of diphosphine ligands (L1-L5) containingbis-phosphino fragments and bis-amido groups as well as intensiveelectron-withdrawing F atoms were synthesized and fullycharacterized. The structures of the prepared complex ofPd-L5demonstrate that as forL5, the incorporated two phosphinofragments participate in the chelation to the Pd center inverselyalong with two Cl-ligands to present a typical square-planarconfiguration, whereas the two amido groups simultaneouslydevelop a hydrogen-bond interaction with Cl-ligands to facilitatethe timely dissociation of Cl-ligands from the Pd center. It wasfound thatL5enabled the Pd complex to be more active in thealkoxycarbonylation of alkynes with MeOH for the synthesis ofbranched/linear alpha,beta-unsaturated carboxylic esters with general yields of 60-89%. InL5, the incorporated diphosphino fragments,diamino groups, and F atoms conferred a catalytic effect to the Pd complex synergetic toward the reaction.

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