Calciferol and its relatives. XV. The preparation of des-AB-cholest-8-ene-8-carbaldehyde (1 beta-[(1R)-1,5-dimethylhexyl]-3a alpha, 6,7,7a beta-tetrahydro-7a beta-methylindane-4-carbaldehyde) and 9 alpha-chloro-des-AB-cholestan-8-one (5 alpha-chloro-1 beta-[(1R)-1,5-dimethylhexyl]-7a beta-methyl-trans-perhydroindan-4-one).