Chemistry of the tricarbonyliron complexes of calciferol and ergosterol.

Calciferol affords α- and β-tricarbonyliron complexes in the ratio ca. 2 : 1. Oxidation of the α-complex gives the relatively stable calciferone derivative. For comparison the tricarbonyliron complex of ergosterol was likewise oxidised to the 3-ketone. This stable compound could be reduced by lithium hydrido-tri-t-butoxyaluminate to give, after decomplexing, the previously unknown epiergosterol in good yield.