presence of 0.2 equivalents of tin(IV) chloride at 80 °C gave diethyl (3-phenyl-1H-inden-2-yl)malonate. Diethyl hydroxy(3-phenyl-1H-inden-2-yl)malonate was also converted into the latter product on heating at 80 °C in the presence of 0.2 equivalents of tin(IV) chloride. The Lewis acid promoted reaction of 1,1-diarylallenes with ketone derivatives was examined. The tin(IV) chloride promoted reaction of diarylallenes