Highly selective catalyst systems for the hydroformylation of internal olefins to linear aldehydes

Readily accessible and highly efficient: Substituted 2,2′-bis(diphenylphosphanylmethyl)-1,1′-binaphthyl (NAPHOS) ligands 1 can be readily prepared from 2,2′-bis(dichlorophosphanylmethyl)-1,1′-binaphthyl. Especially ligands with electron-withdrawing aryl substituents (for example, 3,4,5-F3C6H2 (instead of Ph), 1a) show a remarkable high activity and n:i selectivity in the rhodium-catalyzed hydroformylation of internal olefins (see scheme).