
%0 Journal Article
%A Cambie, Richard C. 
%A Clark, Russell B. 
%A Rutledge, Peter S. 
%A Rustenhoven, J. J. 
%T Experiments Directed Towards the Synthesis of Anthracyclinones. XXXVI Asymmetric Dihydroxylations of Alkylidene Anthracyclinones
%J Australian Journal of Chemistry
%D 1999/08/27
%V 52
%N 8
%P 781-800
%K 
%R https://doi.org/10.1071/CH99014
%U https://www.publish.csiro.au/paper/CH99014 
%X The methylidene tetracycle (2) has been synthesized in 11 steps from quinizarin (5) in an overall yield of 38% by using a highly ecient selective dihydroxylation step and an intramolecular ene cyclization. Also prepared with the selective dihydroxylation methodology were the silyloxy alkene (3) and the 6-demethoxy alkene (4). A mixture (1 : 2) of the (E)- and (Z)-isomers of the ethylidene compound (6) has been prepared by similar methods. The products resulting from the reactions of AD-mix-&#945; and AD-mix-&#946; on the alkenes (1)&#8211;(3) and (6) have been investigated and their stereochemistries assigned by using 1 H n.m.r. and NOESY experiments, and molecular modelling of acetonide derivatives. An X-ray crystal structure of the acetate (64) has confirmed the relative stereochemical assignments. 
