Rhodium-catalyzed cyclic carbonylation of 2-phenylethynylbenzamide under water-gas shift reaction conditions

Under water-gas shift reaction conditions, Rh-6(CO)(16)-catalyzed carbonyla tion of 2-phenylethynylbenzamide (1a) gave two kinds of products, novel spi ro compound (2a) and 2(5H)-furanone (3a), which were produced by cyclic car bonylation of a carbon-carbon triple bond and the former product is formed by participation of the amide group adjacent to the carbon-carbon triple bo nd in the cyclization. The reaction of 2-naphthylethynylbenzamide (Ib) affo rded the corresponding spiro compound 2h and two furanones 3h and 4h. Furan one 4h is a structural isomer of 3h and was demonstrated to be a precursor of 2h. (C) 1999 Elsevier Science S.A. All rights reserved.