Reactions of Lithium Silylcuprates with Pyrazolium and Indazolium Salts

• Published in: European Journal of Organic Chemistry Vol. 2007; no. 36; pp. 6089 - 6096
• Main Authors: González-Nogal, Ana M., Calle, Mariola, Cuadrado, Purificación
• Format: Book Review Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.12.2007; WILEY‐VCH Verlag; Wiley
• Subjects: Chemistry; Chemistry, Organic; Enaminoimines; Heterocycles; Physical Sciences; Science & Technology; Silicon; Silylindazolines; ACETYLENES; silicon; silylindazolines; heterocycles; SILYL-CUPRATION; enaminoirnines
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.200700742

Although pyrazolium salts have been shown to be unreactive toward lithium carbocuprates, these substrates were opened by lithium silylcuprate reagents to give versatile N‐silylated β‐enaminoimines stabilized by coordination of the silyl group with both nitrogen atoms. In contrast, the behaviour of indazolium salts on treatment with the same reagents is more complex. Depending on the substitution patterns of the indazolium salts, the nature of the silylcuprate and even on the temperature, we obtained 3‐silylindazolines and other interesting products resulting either from the opening of the heterocyclic ring or from modification by its opening/closing.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)