Organic syntheses by means of noble metal compounds XXI. Decarbonylation of aldehydes using rhodium complex

Five-coordinate dicarbonyl complexes of rhodium(I): [RhX(CO)2(PPh3)2] (X = Cl, Br, I)

“…The existence of complexes 2 has implications for various reactions catalysed by phosphine complexes of rhodium, especially carbonylation and decarbonylation reactions. Under mild conditions [RhCI(P.Ph,),] is an effective reagent for the stoichiometric decarbonylation of aldehydes and aryl or aroyl halides, but complex l a (which is formed) is not (5,7,15,18). Under more rigorous conditions each material is an effective catalyst for such decarbonylation reactions, and intermediates are formed which contain alkyl and hydrido or halogen ligands (15)(16)(17)(18)(19)(20)(21).…”

A General and Convenient Method for the Rhodium‐Catalyzed Decarbonylation of Aldehydes

“…[1] Three years later the same authors reported the first example of a rhodium-catalyzed decarbonylation with 0.5 % of Rh(CO)A C H T U N G T R E N N U N G (PPh 3 ) 2 Cl at temperatures above 200 8C. [2] The high temperature did cause some side reactions and in 1978 Doughty and Pignolet described a milder procedure with RhA C H T U N G T R E N N U N G (dppp) 2 Cl [dppp = 1,3-bis(diphenylphosphino)propane].…”

Recollections of organopalladium chemistry

“…During our mechanistic studies on Pd-catalyzed carbonylation described later, we found Pd and Rhcatalyzed decarbonylation of acyl halides and aldehydes [8]. We proposed that the ®rst step of the decarbonylation is the oxidative addition of acyl halides and aldehydes to form the acylpalladiums 12 and 13.…”

“…Also the Rh-catalyzed or promoted decarbonylation of acyl halides and aldehydes proceeds more smoothly. Stoichiometric decarbonylation of acyl halides and aldehydes with Wilkinson complex took place at room temperature, and catalytic decarbonylation at high temperature (Scheme 19) [8]. …”