Tandem Regioselective Hydroformylation-Hydrogenation of Internal Alkynes Using a Supramolecular Catalyst.

New supramolecular ligands containing an acyl guanidine function were designed based on the strategy of increasing the π-acceptor ability of phosphine ligands by introducing electron-withdrawing groups. By applying this novel catalytic system, a general protocol for the Rh-catalysed hydroformylation-hydrogenation of unsymmetrical internal alkynes, functionalized with a carboxylic acid, was found to furnish aliphatic aldehydes in high regio- and chemoselectivities. Control experiments confirm the enzyme-like supramolecular catalyst mode of action.