-Tertiary Propargylamine Synthesis via KA²-Type Coupling Reactions under Solvent-Free Cu^I-Zeolite Catalysis

The potential of copper(I)-zeolite catalysis was evaluated in the three-component KA(2)-coupling mediated synthesis of a-tertiary propargylamines. Our archetypal copper(I)-doped zeolite Cu-I-USY proved to be efficient under ligand- and solvent-free conditions at 80 degrees C. Usable up to four times, this catalytic material enables the coupling of diverse ketones, alkynes, and amines with a broad functional group tolerance. A decarboxylative and a desilylative version, respectively, involving an alkynoic acid and trimethylsilylacetylene as alkyne surrogates, was also set up to bypass selectivity issues and/or to access a-tertiary propargylamines that are unattainable under standard KA(2) conditions. Interestingly, the KA(2)-type coupling reactions were successfully linked to other Cu-I-catalyzed reactions, thus resulting in sequential one-pot processes under full Cu-I-USY catalysis.