The concept of non-conjugated-to-conjugated double bond isomerization as a triggering mechanism for a calicheamicin model was tested. A bicyclo [7.3. 1] enediyne framework was prepared with a bridgehead double bond and an acetonyl side chain. Base-promoted exchange failed to produce the conjugated isomer. Computational analysis suggested that additional conjugating groups would favor the isomerization, but experiment proved that ...
