Pj. Boniface et al., EXPERIMENTS DIRECTED TOWARDS THE SYNTHESIS OF ANTHRACYCLINONES .19. ELABORATION OF 2-FORMYLQUINIZARIN THROUGH A WITTIG REACTION, Australian Journal of Chemistry, 47(3), 1994, pp. 441-449
Reaction of 2-formylquinizarin dimethyl ether (3) with the dimethoxy y
lide (6) gives an alpha,beta-unsaturated ester (8) which on hydrogenat
ion, reduction and methylation gives the tetramethoxyanthracene dieste
r (18). When linked to work by Dotz and Popall this sequence provides
a route to (+/-)-4-demethoxydaunomycinone.