The Retro‐Hydroformylation Reaction

Abstract

Hydroformylation, a reaction that adds carbon monoxide and dihydrogen across an unsaturated carbon-carbon multiple bond, has been widely employed in the chemical industry since its discovery in 1938. In contrast, the reverse reaction, retro-hydroformylation, has seldom been studied. The retro-hydroformylation reaction of an aldehyde into an alkene and synthesis gas (a mixture of carbon monoxide and dihydrogen) in the presence of a cyclopentadienyl iridium catalyst is now reported. Aliphatic aldehydes were converted into the corresponding alkenes in up to 91% yield with concomitant release of carbon monoxide and dihydrogen. Mechanistic control experiments indicated that the reaction proceeds by retro-hydroformylation and not by a sequential decarbonylation-dehydrogenation or dehydrogenation-decarbonylation process.

Toward a mild dehydroformylation using base-metal catalysis

“…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. 3).…”

Transition‐Metal‐Catalyzed Decarbonylative Coupling Reactions: Concepts, Classifications, and Applications

“…This protocol proved to be applicable to complex molecules synthesis and was used to achieve a three‐step synthesis of (+)‐yohimbenone. In the same year, a similar transformation was achieved with an iridium complex by Nozaki and co‐workers …”

“…In the samey ear, as imilart ransformation was achievedw itha n iridium complex by Nozakiand co-workers. [66] The retro-hydrocarbonylation strategyh as also contributed to the perception that aliphatic amides can be successfully employed to achieveolefins in adecarbonylative fashion.…”

Reverse-hydroformylation: a missing reaction explored

“…Retro-hydroformylation of aliphatic aldehydes. 5 In summary, both reports reflect remarkable progress on acceptor-and acceptorless-dehydroformylation process for the conversion of large feedstock aliphatic aldehydes into more valuable olefins and marked as important milestone in the area of chemical synthesis. Future direction would be opened up for the utilization of more economical first row transition-metals for dehyroformylation process and renewable biomass derivatives as an alternative for the effective production of synthesis gas enabling sustainable approach for synthesis gas production.…”

“…The formation of alkenes is due to reversible hydroformylation reaction of aldehydes. Very recently, Nozaki and co-workers have reported an unprecedented retrohydroformylation reaction 5 catalysed by a well-defined iridium-based catalyst for the direct, selective conversion of aliphatic aldehydes into the corresponding alkenes with the concomitant generation of syngas (Fig. 5).…”