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Synlett 1996; 1996(1): 89-91
DOI: 10.1055/s-1996-5303
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Synthesis and Cycloaromatization of Enyneallenes: New Model Systems for the Neocarzinostatin Chromophore

Norbert Krause* , Michael Hohmann
  • *Institut für Organische Chemie und Biochemie der Universität Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, GERMANY
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Publication Date:
31 December 2000 (online)

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Acceptor substituted dienediynes 10 with an endocyclic double bond were synthesized and submitted to cuprate 1,6-addition reactions. The resultant enyneallenes serve as new model systems for the neocarzinostatin chromophore since they undergo Myers cyclization to diradicals 12. If these possess a hydrogen atom at C-2’, rearrangement to α,β-unsaturated esters 13a/b takes place; with a crossover experiment it was shown that the hydrogen atom is transferred in an intramolecular fashion. In contrast to this, diradical 12c with two methyl groups at C-2’ abtracts hydrogen atoms from the solvent to give saturated ester 14c.

Neocarzinostatin chromophore - Myers cyclization - Enyneallenes - Organocuprates 1,6-Addition

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