| abstract |
Steroid compounds represented by general formulae (I), (II) or (III), wherein R 1 and R 2 each represents a hydrogen atom or a hydroxyprotecting group, R represents -CH 2 -X, a carboxyl group or a protected carboxyl group, X represents a substituent such as a hydroxy group, A 1 represents an aryl group, a lower alkyl group or an aralkyl group, and Z 1 , Z 2 , Z 3 and Z 4 each represents a hydrogen atom, a hydroxy group or a protected hydroxy group. The steroid compounds are useful as intermediates for synthesis of vitamin D 3 derivatives having a hydroxy group in the la position. |