Rhodium(I) acetylacetonato complexes containing phosphinoalkynes as catalysts for the hydroboration of vinylarenes

Three novel rhodium(I) acetylacetonato (acac) complexes bearing phosphinoalkynes (Ph2PCC-t-Bu, Ph2PCCPPh2, and Ph2PCCCCPPh2) have been prepared and characterized fully. Addition of B(2)cat(3) (cat = 1,2-O2C6H4) to Rh(acac)(Ph2PCC-t-Bu)(2) (1a) led to zwitterionic Rh(eta(6)-catBcat)(Ph2PCC-t-Bu)(2) (2a), the first example of this type of compound to contain monodentate phosphine ligands. All new rhodium complexes have been investigated for their ability to catalyse the hydroboration of vinylarenes.