Rhodium-catalysed carbonylation of 2-alkynylphenols 1 under water-gas shift reaction conditions gives benzofuranone derivatives 2 and coumarin derivatives 3 in high yield (up to 96%, 2∶ 3= 65∶ 35), in which the hydroxy group adjacent to the carbon–carbon triple bond participitates in the cyclic carbonylation.
