Neue Bi(cyclopropylidene) durch CuCl2-katalysierte ‘Carben-Dimerisieiung’ von 1-Bromo-1-lithiocyclopropanen

Authors

  • Markus Borer,

    1. Departement für Chemie und Biochemie der Universität Bern, Freiestrasse 3, CH-3012 Bern
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    • Teil der Dissertation [2].

  • Markus Neuenschwander

    Corresponding author
    1. Departement für Chemie und Biochemie der Universität Bern, Freiestrasse 3, CH-3012 Bern
    • Departement für Chemie und Biochemie der Universität Bern, Freiestrasse 3, CH-3012 Bern
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  • 19. Mit. über Kupplungsreaktionen. 18. Mitt.: [1].

Abstract

New Bi(cyclopropylidenes) by CuCl2-Induced ‘Carbene Dimerization’ of 1-Bromo-1-lithiocycIopropanes

A series of so far unknown bi(cyclopropylidenes) 5 are prepared in a simple one-pot reaction by halogenolithio exchange between 1,1-dibromocyclopropanes 1ac as well as 1ei and BuLi at −95°, to give 1-bromo-1-lithiocyclopropanes 2ac as well as 2ei, followed by treatment with CuCl2 at low temperature and a simple workup at room temperature (Table 1). The influence of reaction parameters on yields of 5 (Tables 2, 4, and 5) and diastereoselectivity of the reaction 2 → 5 (Table 3) are discussed. In view of an elucidation of the reaction mechanism, first kinetic experiments of the quantitative reaction 1c2c5c are reported.

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