A general and regiospecific route to tetracyclic alkenes in the 11-deoxyanthra'cyclinone series

Synthesis and cytotoxic activity of tetracenomycin D and of saintopin analogues

Regiospecific synthesis of title compounds is based either on cycloaddition of ketene acetals derived from Hagemann's ester or of homophthalic anhydrides. Thus, tetracenomycin D and 3,8-di-O-methyl saintopin have been prepared in few steps. New derivatives of 10-deoxysaintopin have been also obtained. Evaluation of their cytotoxicity against L1210 leukemia cells are reported.

An efficient synthesis of peri-hydroxy aromatic compounds via a strong-base-induced

An efficient synthesis of peri-hydroxy aromatic compounds has been accomplished via a strong-base-induced [4+2] cycloaddition of homophthalic anhydrides with alpha-sulfinyl-substituted derivatives of enolizable enones. The unsubstituted enones did not undergo an efficient [4+2] cycloaddition reaction with homophthalic anhydrides, presumably due to their enolization under the basic reaction conditions. The sulfinyl group not only promotes the cycloaddition reaction but also undergoes in situ elimination under the reaction conditions to afford the peri-hydroxy aromatic compounds in a single step. The application of this methodology for the synthesis of a key intermediate of antitumor antibiotic fredericamycin A is described. PM3 calculations of various 2-substituted cyclopentenones as well as the mechanism of the cycloaddition are also discussed.