Reaction of dichloroketone 2 with NEt3 gave indenone (4) in high yield. Cat
odic reaction of 2 in the presence of C/Pt electrodes afforded the rearrang
ed product 3 in high yield besides a small amount of chlorohydroxyketone 5.
Reaction of rearranged dichloroketone 3 with NEt3 provided indenone (4) as
the sole product. The mechanism of these reaction was discussed.