Transition metals in organic synthesis: Hydroformylation, reduction and oxidation

Heteropolyacids enhanced the catalytic activity of Rh6(CO)16 in the hydroformylation of alkenes

“…An increase in the ratio of CO-H 2 from 1 : 1 to 4 : 2 and 5 : 1 decreased the conversions of styrene from 97 to 75 and 28%, respectively (Table 4, entries 1-3). However, the decrease in the CO-H 2 ratio to 2 : 4 and 1 : 5 gave relatively high conversions (92 and 88%) with a slight drop in selectivity to the branched aldehyde B (Table 4, entries 4,5). No products were obtained in the absence of hydrogen (Table 4, entry 6).…”

“…The catalytic activity strongly depends on the P/Rh ratio, but the regioselectivity is not markedly Materials, Nanoscience and Catalysis affected by the P/Rh ratio. 20 Other rhodium-based catalyst systems, including (OC) 4 3 , have been used in the hydroformylation of 1-hexene, styrene and some phosphino-, amino-and amido-alkenes. In general the catalysts showed very similar activity and selectivity.…”

“…• C but the selectivities of the reactions decreased by forming the other aldehyde isomers B 2 , B 3 and B 4 .…”