(±)-Metaphanine (49), which is a member of hasubanan alkaloids and possesses an intramolecular hemiketal ring, was synthesized. The keto-lactam (5)³⁾ was derived to the diacetoxy-ketal (13) via the O-acetyl-ketolactam (11). The compound (13) was oxidized to the 10-oxo compound (16) which was reduced stereoselectively to the trans diol-lactam (22), a C₁₀-hydroxy group of which was selectively protected by an acetyl group or by a tetrahydropyranyl group to give the trans 10-acetoxy compound (23) or the monotetrahydropyranyl ether (33), both of which were oxidized and hydrolyzed to provide (±)-7-ethyleneketal-16-oxo-metaphanine (36). The selective reduction of the lactam carbonyl group of the compound (36) by the Borch's method⁴⁾ gave (±)-7-ethyleneketal-metaphanine (44) which was hydrolyzed to give (±)-metaphanine (49).