Highly regioselective isomerization-hydroformylation of internal olefins to linear aldehyde using Rh complexes with tetraphosphorus ligands

A series of new pyrrole-based tetraphosphorus ligands were synthesized and used for Rh-catalyzed isomerization-hydroformylation of internal olefins. It was found that the substituents at the 3,3',5,5'-positions of the biphenyl greatly effected the linear selectivity, and the alkyl-substituted tetraphosphorus ligands gave the best results (for 2-octene, n:i up to 207, for 2-hexene, n:i up to 362).