Selective hydroformylation with a recoverable dirhodium µ-thiolato complex

The dimeric precursor complex {Rh2[µ-S(CH2)3N(Me)2]2(Cod)2}, (cod = cyclo-octa-1,5-diene), with PPh3 catalyses the hydroformylation of hex-1-ene, under mild conditions, into heptanals with high yields and selectivities; owing to the presence of the amine group the rhodium catalyst can be quantitatively recovered from the reaction mixture by adding dilute H2SO4, and reused without loss of activity.