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Two related methods to synthesize (plus or minus)-calicheamicinone, the aglycon of the calicheamicin antitumor antibiotic, are reported. Both compounds represent difficult synthetic targets and are of interest with regard to the mode of action of enediyne antitumor agents. The syntheses showed high levels of steroselectivity and that a calicheamicinone of unnatural stereochemistry may be more efficient at producing double strand cuts in DNA, than natural stereochemical material.

The active principles of the anticockroach/insecticidal powder 'la hierba de la cucaracha', which is derived from the leaves of the Haplophyton cimicidum plant, includes a variety of alkaloids including aspidophytine and haplophytine. The complex structures of these two alkaloids have yet to be determined. A study reports the short, convergent enantioselective synthesis of asidophytine. Asidophytine synthesis will likely lead to the synthesis of haplophytine.

Phase transfer has proven to be a remarkably enantioselective alkylation catalyst in the alkylation of a 3-oxygenated propionic ester equivalent. It is applicable to other enolates, with the enantioselectivity varying predictably with the electronic effect of remote substituents on the enolate. An analysis of the alkylation process emphasizes the importance of charge density and entropy in determining the degree of enantioselectivity. Results offer fresh insights into catalytic enantioselective phase transfer reactions and a novel approach for the synthesis of various building blocks.

Two related methods are capable of synthesizing 2S and 2R-isomers of calicheamicinone which shows natural stereochemistry. The synthesis involves ester exchange of beta-keto ester with ClCH2CH2OH which gave ketene acetal on treating with K2CO3. Intermediate reactions of the various intermediate compounds formed include deprotonation, Diels-Alder cycloaddition, silylation and reduction of the primary alcohol generated from an alpha-isomer. The final synthetic 2S and 2R calicheamicinone resulted from acid hydrolysis which separated the two protecting groups.

Characterizes two related techniques for the synthesis of (...)-calicheamicinone, the aglycon of the antitumor antibiotic calichemacin gamma1I. Information on the chemistry and biological properties of calicheamicin gamma1I; Evidence that as a synthetic target, calicheamicin gamma1I represents a large number of complex problems; Development of the synthetic plan; Discussion on the study.