Erratum: Functionalization of vitamin D metabolites at C-18 and application to the synthesis of 1α,18,25-trihydroxyvitamin D3 and 18,25-dihydroxyvitamin D3 (Tetrahedron Letters, 1992, 33 (1503-1506))

1. Valles, M.J.
2. Castedo, L.
3. Mourino, A.