1973 年 21 巻 2 号 p. 296-307
5α-and 5β-2-oxosantanolide (XIII and XXIII) have been synthesized from known 2-acetoxy-α-and γ-tetrahydrosantonin (VIII and XIX), respectively, which has previously been obtained from (-)-santonin. Nuclear magnetic resonance, optical rotatory dispersion and circular dichroism spectra of XIII and XXIII are discussed.