Homogeneous gold-catalyzed synthesis of biphenyls and furfuryl-substituted arenes

The synthesis of phenyl- and furfuryl-substituted furans and their unique gold-catalyzed transformation to biaryl compounds and furfuryl arenes was investigated. With the aryl-substituted substrates the reactions proceeded very well, and in the case of a chloro-substituent in o-position of the phenyl group a minor side-product, that might be explained by a neighboring-group participation of that chloro-substituent, was isolated. In the case of the furfuryl-substitution the side reactions become more relevant, the two side-products provide evidence for a carbeniumion as intermediate that is transformed into a more stable furfuryl cation by a C-C bond cleavage. (C) 2002 Elsevier Science B.V. All rights reserved.