Concise synthesis of (4S,5S)-4,5-(isopropylidenedioxy)-2-cyclopentenone and a novel C2-symmetric ketone

A new and concise synthesis of the useful synthetic intermediate 1 is described which also allows access to a novel C 2 -symmetric keton 2 . The route relies on the Sharpless asymmetric dihydroxylation of fulvenes.