Copper-Impregnated Magnetite as a Heterogeneous Catalyst for the Homocoupling of Terminal Alkynes

Copper-impregnated magnetite is a versatile heterogeneous catalytic system for the synthesis of 1,3-diynes by the homocoupling of terminal alkynes. This catalyst does not require the use of pressurized oxygen as the oxidant and it does not need a solvent or harsh conditions to give the expected products. Moreover, the catalyst can be removed from the reaction medium simply by using a magnet. The reaction occurs at the lowest copper loading reported for any heterogeneous catalyst.This work was supported by the Spanish Ministerio de Economía y Competitividad (M.E.C) (Consolider Ingenio 2010 CSD2007-00006, CTQ2011-24151) and by the Generalitat Valenciana (G.V) (Prometeo 2009/03, FEDER). J.M.P. and R.C. thank the M.E.C. (FPI program) and the G.V., (PROMETEO program), respectively, for their fellowships