Acyl cyanides palladium-catalyzed

Murahashi, S., Naota, T., Nakajima, N. Palladium-catalyzed decarbonylation of acyl cyanides. J. Org. Chem. 1986, 51,898-901. 

The palladium-catalyzed decarbonylation of aromatic acyl cyanides proceeds at 120 °C to give the corresponding nitriles in excellent yield. Since acyl cyanides are readily prepared by the ruthenium-catalyzed oxidation of cyanohydrins with BuKDOH this represents a good method for the conversion of aldehydes to nitriles under mild conditions (Scheme 29). 

Murahashi S, Naota T, Nakajima N (1986) Palladium-catalyzed decarbonylation of acyl cyanides. J Org Chem 51(6) 898-901. doi 10.1021/jo00356a029... 

Decarbonylation of acyl cyanides has also been known since Blum reported a rhodium-catalyzed reaction in 1967 (Eq. (6.16)) [35]. Later, this reaction was significantly improved by using a palladium-based catalyst [36]. 

The use of oxidative addition of a C-CN bond in a more elaborate synthetic process was first demonstrated in 1994 by Nozaki and Takaya. The palladium-catalyzed reaction of acyl cyanide 64 with terminal alkyne 65 yields nitrile 66 in the reaction, alkyne 65 is formally inserted into a C(=0)-CN bond in 64 (Scheme 6.12) [37]. It is proposed that the reaction is initiated by oxidative addition of 64, which acylates 65 to form alkyne 68, along with hydride-palladium 69. Subsequent hydrocyanation affords nitrile 70, which finally isomerizes to 66 under these catalytic conditions. 

---