A new candidate for a properly substituted CD ring component of vitamin D3 via intramolecular asymmetric olefination of a 1,3-cyclopentanedione derivative

Article abstract of DOI:10.1021/jo00099a002

A highly diastereoselective synthesis of hydrindenone derivative 5 (98% de) was achieved via diastereotopic differentiation of 1,3-cyclopentanedione derivative 4 by intramolecular Horner-Emmons olefination. In addition, the compound 5 was converted to ketone 2, a new building block for 1α,25-dihydroxyvitamin D₃ (1).