Regio- and Stereoselective Chlorocyanation of Alkynes.

Autor: Barrado AG; Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077, Göttingen, Germany., Zieliński A; Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077, Göttingen, Germany., Goddard R; Max-Planck-Institut für Kohlenforschung, Kaiser Wilhelm Platz 1, 45470, Mülheim an der Ruhr, Germany., Alcarazo M; Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077, Göttingen, Germany.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2017 Oct 16; Vol. 56 (43), pp. 13401-13405. Date of Electronic Publication: 2017 Sep 21.
DOI: 10.1002/anie.201705851
Abstrakt: A variety of terminal and internal alkynes were converted regio- and stereoselectively into (Z)-3-chloroacrylonitriles by treatment with BCl 3 in the presence of stoichiometric amounts of imidazolium thiocyanates. These products could be readily functionalized to provide useful building blocks, thus demonstrating the synthetic value of the method. Preliminary mechanistic studies suggest initial activation of the cationic thiocyanate by the Lewis acid, followed by electrophilic attack of the alkyne. The syn addition of a chloride to the vinyl cation intermediate and final elimination of the thiourea unit afford the desired chloroacrylonitriles.
(© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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