The absolute configuration of avarol, a rearranged sesquiterpenoid hydroquinone from a marine sponge
Abstract
With the aid of circular dichroism, n.m.r. shift reagents, and 13C n.m.r. spectroscopy the absolute stereochemistry has been assigned to avarol {2-[(1R)-1,2,3,4,4a,7,8,8aα-octahydro-1β,2β,4aβ,5-tetramethyl-1-naphthylmethyl]-hydroquinone}, obtained from the marine sponge Disidea avara. Avarol is the first naturally occurring sesquiter-penoid of the 9,4-friedodrimane type to be isolated.