Photoinduced molecular transformations. Part 153. Long-range intramolecular hydroxylation of C(25) of the cholestane side chain

Abstract

Alkoxyl radicals generated by photolysis of the hypoiodites of 5α-cholestan-7α-yl 4-(α-hydroxyphenylmethyl)phenylacetate and 5α-cholestan-7α-yl 3-[4-(α- hydroxyphenylmethyl)phenyl]-propanoate, respectively, abstracted hydrogen from C(25) of their cholestane side chain to give novel macrocyclic lactones. A reductive cleavage of the benzyl ether linkage of these lactones with sodium and liquid ammonia gave 5α-cholestane-7α,25-diol in good yields.