Synthesis, x-ray structure, and properties of fluorocyclopropane analogs of the duocarmycins incorporating the 9,9-difluoro-1,2,9,9a-tetrahydrocyclopropa c benzo e indol-4-one (F2CBl) alkylation subunit

A difluoro substituted cyclopropane analog of the alkylation subunits of the parent members of a class of potent antitumor antibiotics is synthesized. The analog is the first of its kind to contain substitution or functionalization of the reactive center in the natural products. Showing increased reactivity, the analog is found to be less cytotoxic than other duocarmycin derivatives.