Hydroformylation of alkenes and alkynes using a heterobinuclear RhW catalyst

Abstract

Hydroformylation reactions of a series of alkenes and alkynes have been carried out using the heteronuclear RhW catalyst, (CO) 4 W(μ-PPh 2) 2R hH(CO)(PPh 3) ( 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, Ph 2P(CH 2) 3CHCH 2 ( 7) and the corresponding alkyne, Ph 2P(CH 2) 3CCH ( 11) gave similar products using either catalyst system with the alkryne reaction being significantly slower. Reaction of the alkenyl dithiane, S(CH 2) 3SC HCH 2CHCH 2 ( 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.