Calciferol and its relatives. Part 23. An alternative synthesis of Windaus and Grundmann's C19 ketone

Abstract

(–)-(S)-Methyl hydrogen β-methylglutarate was converted into (S)-2,3-dimethylbutyl phenyl sulphone (10). This was used in combination with the aldehyde (2), obtained by oxidation of 1β-[(R)-2-hydroxy-1-methyl-ethyl]-7aβ-methyl-3aα,4,5,6,7, 7aβ-hexahydroindan-4β-yl benzoate (1), to effect a sterospecific synthesis of the secondary alcohol (12) which corresponds to Windaus and Grundmann's C₁₉ ketone.