Copper(<scp>i</scp>)/phosphine-catalyzed tandem carboxylation/annulation of terminal alkynes under ambient pressure of CO₂: one-pot access to 3a-hydroxyisoxazolo[3,2-a]isoindol-8(3aH)-ones

Abstract

A tandem carboxylation/annulation sequence promoted by a copper(<sc>i</sc>)/phosphine catalytic system was developed with simultaneous formation of four novel bonds <italic>i.e.</italic> two C–C bonds and two C–O bonds in a one-pot stepwise manner.