POSSphites—monophosphites derived from incompletely condensed silsesquioxanes

A straightforward three-step synthetic route is followed to obtain nanostructured silsesquioxane based monophosphite compounds 1–3, which we named POSSphites. These compounds, derived from (c-C5H9)7Si7O9(OH)3 and commercially available phenol derivatives, differ mainly in the steric bulk around the phosphorus atom. Preliminary results in the rhodium-catalyzed hydroformylation of 1-octene exemplify the use of these ligands for homogeneous catalysis. High activities, with a turnover frequency of up to 5000 h−1 were obtained. Ligands 1–3 are the first silsesquioxane derived monophosphite ligands to be successfully applied in homogeneous catalysis.