Calciferol and its relatives. Part 20. A synthesis of Windaus and Grundmann's C19 ketone

Abstract

Starting from 1β-[(R)-2- hydroxy-1-methylethyl]-7aβ-methyl-3aα,6,7,7aβ-tetrahydroindane (1) syntheses have been effected of two bicyclic compounds suitable as intermediates for conversion into vitamin D-active products, viz. Windaus and Grundmann's ketone (20){7aβ-methyl-1β-[(1R,4R)-1,4,5-trimethylhex-trans-2-enyl]-3aα,4,5,6,7,7aβ-hexahydroindan-4-one}, and des-AB-cholestane-8β,25-diol (23){4β-hydroxy-1β-[(R)-5-hydroxy-1,5-dimethylhexyl]-7aβ-methyl-3aα,4,5,6,7,7aβ-hexahydroindane}.