HYDROFORMYLATION OF ALKENES AND ALKYNES USING A HETEROBINUCLEAR RH-W CATALYST

Hydroformylation reactions of a series of alkenes and alkynes have been carried out using the heteronuclear Rh-W catalyst, (CO)4 (mu-PPh2)2RhH(CO)(PPh3) (1). The results of these reactions have been compared with corresponding reactions using [Rh(OAC)2]2 as catalyst. Catalysis of a reaction of styrene using 1 gave a very high yield of the branched chain aldehyde containing only a trace of the straight chain isomer. Reactions of the phosphinoalkene, Ph2P(CH2)3CH=CH2 (7) and the corresponding alkyne, Ph2P(CH2)3C=CH (11) gave similar products using either catalyst system with the alkyne reaction being significantly slower. Reaction of the alkenyl dithiane, S(CH2)3SCH-CHCH=CH2 (2), using the Rh-W catalyst (1) gave a higher ratio of linear to branched aldehydes (47 linear:53 branched) than the corresponding reaction using [Rh(OAc)2]2 (25 linear:75 branched). Reactions of vinyl acetate using 1 as catalyst gave a significant amount of linear aldehyde in contrast to reactions using [Rh(OAc)2]2 but reactions of allyl acetate gave similar products for both catalyst systems.