Synthese und Reaktionen der ersten zweifach überbrückten Fiscellane

Synthesis and Reactions of the First Doubly‐Bridged Fiscellanes The synthesis of the novel hexacycle 2 containing a fiscellane framework is described. Starting from Weiss' tetraester 6 , the fiscellane 2 is build up in six steps by successive chemical transformation of the methoxycarbonyl functions using SEM protecting groups. The behaviour of the novel diol 2 towards introduction of several leaving groups is examined. Upon treatment with methanesulfonyl chloride the highly strained hexacycle 2 undergoes a skeletal rearrangement with formation of the triene 4 . Instead of reacting to a doubly‐bridged semibullvalene 3 , the diol 2 gives rise to a new heterocyclic π perimeter 5 when the trifluoroacetyl derivative 12 is treated with sodium iodide in acetone.