Glycerol: a biorenewable solvent for base-free Cu(i)-catalyzed 1,3-dipolar cycloaddition of azides with terminal and 1-iodoalkynes. Highly efficient transformations and catalyst recycling

Abstract

The combination of CuI and glycerol exhibits a versatile and high catalytic activity in the Huisgen cycloaddition of azides and terminal or 1-iodoalkynes under standard bench experimental conditions (room temperature, under air and in the absence of a base) providing a pivotal contribution to Green Chemistry. Since the catalytic reaction: (i) is amenable at low catalyst loading and accessible on a high scale; (ii) tolerates a variety of functionalities (including the presence of a free thio moiety in the substrate); (iii) can be effectively recycled (up to 6 consecutive runs); and (iv) is isolated in a straightforward manner (by simple filtration in the absence of organic solvents at any stage of the synthesis), the practical application of this methodology provides a complementary synthetic tool to the familiar CuAAC reactions.