
TY  - JOUR
A1  - Bercich, MD 
A1  - Cambie, RC 
A1  - Howe, TA 
A1  - Rutledge, PS 
A1  - Thomson, SD 
A1  - Woodgate, PD 
T1  - Experiments Directed Towards the Synthesis of Anthracyclinones. XXV. Synthesis of a Vineomycinone B<sub>2</sub> Methyl Ester Intermediate From Anthrarufin
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1995
VL  - 48
IS  - 3
SP  - 531
EP  - 549
KW  - 
UR  - https://doi.org/10.1071/CH9950531 
N2  - 6-(1'-Formyl)-1,5-dimethoxy-2-(2&#8243;-oxopropyl) anthraquinone (1), a key intermediate in Danishefsky's synthesis of vineomycinone B2 methyl ester (5), has been prepared by a new route from anthrarufin (6) via the intermediate 1-methoxy-2-(2&#8242;-methylprop-2&#8242;-enyl)-5-(2&#8242;-methylprop-2&#8242;-enyloxy) anthraquinone (20). An alternative synthesis of the diketone (40) has been achieved via Claisen rearrangement of (20) and a subsequent ozonolysis of the resulting bis ( methylpropenyl ) anthraquinone (26). Other routes to (1) from anthrarufin have been developed. In one, compound (1) was formed in yields of 10-16% as an anomalous product from the ozonolysis of (27). Ozonolyses of mixtures of (27), (37) and (44), obtained by isomerization of (27), afforded (1) in yields of 28-43%. Isomerization of the diphenol (25) with palladium(II) chloride bis ( acetonitrile ) in refluxing chloroform proceeds at a faster rate than the isomerization of (27), thereby affording the mono isomerized  diphenol (38) in 37% yield. Methylation of (38) affords (37), a known precursor of (1). 
ER  -

