Åkerbladh L, Nordeman P, Wejdemar M, Odell LR, Larhed M
J. Org. Chem. 80 (3) 1464-1471 [2015-02-06; online 2015-01-21]
A palladium-catalyzed CO gas-free carbonylative Sonogashira/cyclization sequence for the preparation of functionalized 4-quinolones from 2-iodoanilines and alkynes via two different protocols is described. The first method (A) yields the cyclized products after only 20 min of microwave (MW) heating at 120 °C. The second method (B) is a gas-free one-pot two-step sequence which runs at room temperature, allowing the use of sensitive substituents (e.g., nitro and bromide groups). For both protocols, molybdenum hexacarbonyl was used as a solid source of CO.