Abstract: Diketohe (1), the degradation product of qinghaosu, was reacted with barium hydroxide octahydrate in methanol to give ketoacid (5) in 76% yield. Its structure and stereochemistry were ascertained by. spectral and X-ray crystallographic methods. Ketoacid(5) was converted into diene(7a) by the Wittig reaction. Diene(7a) was hydrogenated over Reney Ni catalyst in methanol to yield a mixture of (9a), (10a) and (11a) (ratio 3:8:1), in which (9a) was identical with an authentic sample on the basis of the TLC, GC-MS, IR and ¹NHMR spectra of (9b). When the hydrogenation products were treated With Osmium tetroxide' and. Nmethyl-morpholine-N-oxide, hydroxy lactone(12) derived from (9a) was isolated as needle crystals. Further oxidation of (9) or (12) will afford compound (19), the key intermediate in. total synthesis of qinghaosu.