摘要:
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 far 1 alpha,25-dihydroxyvitamin D-3 (1).