Cyanocarbonylation aryl iodides

Pd-catalyzed cyanocarbonylation of aryl iodides with potassium cyanide is effected by 1% of PdPdI(PPh3)2 under 20 atm of CO at 100 °C (Scheme 40). The optimum ratio of KCN to Arl differs from aryl iodide to aryl iodide, and the best yield of aroyl cyanides is usually obtained with 0.5-0.3 equiv of KCN. The direct coupling product (arylcyanide) is produced in negligibly small amount (< 2%) except for the reaction of 2-thienyl iodide, which furnishes a mixture of cyano 2-thienyl ketone (45%) and 2-cyanothiophene (22%, under 8 atm CO, 100 °C, 24 h). Aryl bromides do not work well. 

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