Hydroformylation and related reactions of vinylsilanes catalyzed by siloxide complexes of rhodium(I) and iridium(I)

Authors:

• Ewa Mieczyńska,
• Anna M. Trzeciak,
• Józef J. Ziółkowski,
• Ireneusz Kownacki,
• Bogdan Marciniec

Abstract

Rhodium(I) and iridium(I) complexes of the formula [(cod)Rh(OSiMe ₃)(PPh₃)] (1), [(cod)Rh(OSiMe₃)(PCy ₃)] (2), [(cod)Rh(OSiMe₃)]₂ (3), [(cod)Ir(OSiMe₃)(PCy₃)] (4), and [(cod)Ir(OSiMe ₃)]₂ (5), used as catalysts of hydroformylation of the vinylsilanes Me₃SiCHCH₂, Me₂PhSiCHCH ₂, (MeO)₃SiCHCH₂, and Me₂PhSiCHCHPh at 80 °C and 10 atm of H₂/CO (H₂:CO = 1), produced aldehydes (n + iso) as the main products with yields of up to 100%. In the presence of the iridium complexes (4) and (5), some amounts of ethylsilanes, up to 40%, were obtained, besides aldehydes as a result of hydrogenation of the substrates. In the presence of the rhodium complexes (1) and (2), isomerization of iso-aldehydes to 1-siloxypropenes was observed under the reaction conditions. Under 10 atm of H₂, the rhodium complexes appeared to be very effective catalysts of vinylsilanes hydrogenation. The hydrogenation reaction products, in addition to ethylsilanes, also included products of homocoupling of vinylsilanes (hydrogenated and non-hydrogenated). © 2005 Elsevier B.V. All rights reserved.