Ruthenium complex catalyzed intermolecular hydroacylation and transhydroformylation of olefins with aldehydes

Catalytic Markovnikov and anti‐Markovnikov Functionalization of Alkenes and Alkynes: Recent Developments and Trends

“…Among others, [200] zerovalent Ru complexes such as [Ru 3 (CO) 12 ], [Ru(cod) 2 ], and [Ru(cod)-(cot)] (cot is cyclooctatetraene) have been employed as catalysts for the addition of various aromatic and heteroaromatic aldehydes to olefins (40-54 % yield). [201] Often these [203b] to afford the corresponding linear ketones (32-92 % yield). In this reaction, aldimines are supposed to be the key intermediates (Scheme 67), which allow for a more facile C À H activation through cyclometallation.…”

Toward a mild dehydroformylation using base-metal catalysis

“…4 Reports of the reaction do exist as early as the 1960's, often using rhodium, ruthenium, or palladium, and usually at high temperature and/or with low selectivity for the olefin over other products. 5–8 While the rarity of this reaction might seem surprising given the ubiquity of hydroformylation, this can be ascribed to the presence of several challenges, including inherent endothermicity and potential for side reactivity such as hydrogenation of the product alkenes. 9 Another barrier is provided by examining the microscopic reverse of the hydroformylation mechanism.…”

“…13 While such reactivity had been observed previously, this catalyst system represents a significant improvement over the earlier methods, where yields were low, ester side products were observed, and the reaction had to be performed at high temperature and high pressure of carbon monoxide. 8 In the wake of that development, Nozaki and coworkers described a method of acceptorless dehydroformylation using a carefully engineered iridium complex to produce olefins with H 2 and CO as the sole by-products. 14 The optimized catalyst, a well-defined, bulky N -heterocyclic carbene (NHC) hydroxytetraphenylcyclopentadienyl iridium species ( 1 ), provides unprecedented selectivity for dehydroformylation over other potential side processes and good thermal stability (Fig.…”

Rh-catalyzed C–C bond cleavage by transfer hydroformylation

“…Thus, we needed a strategy for diverting the acyl–Rh III –hydride towards dehydroformylation. To date, olefins generated by dehydroformylation have been observed in low-quantities during decarbonylations (15,17,18). One report describes the use of stoichiometric Ru for dehydroformylation of butyraldehyde (19), while another uses heterogeneous Rh or Pd catalysts for transforming steroidal aldehydes at 160–300 °C (20).…”