Copper-Catalyzed Difunctionalization of Propargylic Carbonates through Tandem Nucleophilic Substitution/Boroprotonation.

Highly functionalized organic molecules are in high demand, but their preparation is challenging. Copper-catalyzed transformation of alkynyl- and allenyl-containing substrates has emerged as a powerful tool to achieve this objective. Herein, an efficient copper-catalyzed difunctionalization of propargylic carbonates through tandem nucleophilic substitution/boroprotonation has been developed, affording the formation of thiol-, selenium-, and boron-functionalized alkenes with high yield and stereoselectivity. Two distinct catalytic mechanisms involving a single reaction without any requirement of catalyst change were successfully demonstrated.