Dienediyne core

From a tactical perspective, early retrosynthetic removal of the epoxy dienediyne core must dominate all synthetic planning for (+ )-neocarzi-nostatin, since its presence in any intermediate will render that molecule highly susceptible to nucleophilic attack, and will jeopardise the success of all the remaining chemistry. In essence, it would be strategically advisable to install the epoxy dienediyne unit late in a forward total synthesis of ( + )-neocarzinostatin. 

Scheme 7-20 Synthesis of the epoxy dienediyne core of NCS chiomophore (Myers et al.).

Although most work relating to the neocarzinostatin chromophore has concentrated upon the dienediyne core of the molecule, a number of studies concerning the naphthoate moiety have also appeared [175-179]. 

The enediyne core structure of the neocarzinostatin chromophore has been ass -bled by combining an intramolecular carbopalladation starting from a bromoenediyne (Scheme 24, Eq. or a 1,1-diiodoenediyne with a subsequent Stille coupling (Scheme 24, Eq. The latter synthesis of a dienediyne starting from the diiodoenediyne... 

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