The Mechanism of the Dötz Reaction: Chromacyclobutenes by Alkyne–Carbene Coupling?

Authors

  • Prof. Dr. Peter Hofmann,

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    1. Anorganisch-chemisches Institut der Technischen Universität München, Lichtenbergstrasse 4, D-8046 Garching (FRG)
    • Anorganisch-chemisches Institut der Technischen Universität München, Lichtenbergstrasse 4, D-8046 Garching (FRG)
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  • Dipl.-Chem. Martin Hämmerle

    1. Anorganisch-chemisches Institut der Technischen Universität München, Lichtenbergstrasse 4, D-8046 Garching (FRG)
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  • This work was supported by the Stiftung Volkswagenwerk and by the Fonds der Chemischen Industrie.

  • Dedicated to Professor Hans Hofmann on the occasion of his 60th birthday

Abstract

original image

Chromacyclobutenes 2, which have been postulated as intermediates on several occasions, are unrealistic structures with incomplete electron shells and high energy. According to model calculations vinylcarbene complexes 3/4 are much more stable isomers and can be formed almost without activation energy from alkyne-carbene complexes 1. The different modes of coordination of the structure continuum 1–6 can be interpreted and predicted as a function of the metal complex MLn.

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