From Stoichiometric to Catalytic Binuclear Elimination in Rh–W Hydroformylations. Identification of Two New Heterobimetallic Intermediates

Cyclopentene hydroformylation, both stoichiometric and catalytic, is performed starting with Rh4(CO)12 and CpW(CO)3H as precursors. Synergism is observed. Isotopic labeling experiments confirm 30% of the product formation occurs via a catalytic binuclear elimination reaction. Two new intermediates are spectroscopically identified using band target entropy minimization and DFT, namely, RhW(CO)7Cp and CpW(CO)3H-C5H9CORh(CO)4. The latter intermediate appears to be hydrogen bonded via two simultaneous η5-C5H4–H···OC interactions, one with the CO group on the acyl moiety and the other with a CO on rhodium.