[Pd(PPh3)2(saccharinate)2]-general catalyst for Suzuki-Miyaura, Negishi cross-coupling and C-H bond functionalization of coumaryl and pyrone substrates

The potential of complex [Pd(PPh3)(2)(saccharinate)(2)] 1 in catalyzing Suzuki-Miyaura cross-coupling of 4-halo and 4-bromomethyl coumaryl and pyrone substrates with different aryl boronic acids has been explored. Excellent yields of the desired products are obtained in competitive reaction time and under relatively mild conditions. Negishi cross-coupling of 4-coumaryl tosylate with aryl and allcylzinc reagents has also been performed with good yields of the cross-coupled products obtained in most cases. Intramolecular C-H bond functionalization of coumaryl ethers also furnished very high yields of synthetically attractive tetracyclic ring systems exhibiting the potential of I as a powerful catalyst in synthetically important reactions. (C) 2012 Elsevier Ltd. All rights reserved.