Cyclocotrimerization of Alkynes with Nitriles to Form Pyridines

1 Cyclocotrimerization of Alkynes with Nitriles to Form Pyridines 

Cobalt-catalyzed cyclocotrimerization of alkynes and nitriles was pioneered by Wakatsuki, Bonneman, and co-workers [55], Highly selective intramolecular versions of this powerful pyridine-ring annulation were developed further using cobalt, rhodium, and nickel catalysts by Vollhardt, and others [53], These reactions include 

Varela et al. investigated the intermolecular cyclocotrimerization of methyl pro-piolate with several electron-deficient nitriles using a catalytic system comprising complex 10 and triethylammonium chloride (Table 3.13) [58]. The reaction of a 1 1 mixture of propiolate and methyl cyanoformate, tosyl cyanide, or trichloroacetoni-trile proceeded in dimethylformamide (DMF) at room temperature for 12 h to deliver 

53% with 3 equiv of TsCN 50% with 3 equiv of Q3CCN 

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