The chromophore component (1)'of the antitumor agent neocarzinostatin2 exhibits potent cytotoxicity and DNA-cleaving a~ tivity.~ DNA cleavage is believed to be initiated by an exceptionally facile nucleophilic addition of thiol to C12 of 1 followed by a rapid rearrangement reaction leading to the formation of a carbon-centered biradi~ al.~ The highly strained carbocyclic skeleton of 1 and unusual assembly of functional groups along its ...
