Regioselective Synthesis of Silylated Pyrazolines and Indazolines by Reaction of Pyrazolium and Indazolium Salts with Silyllithium Reagents
作者:Ana M. González-Nogal、Mariola Calle、Luis A. Calvo、Purificación Cuadrado、Alfonso González-Ortega
DOI:10.1002/ejoc.200500438
日期:2005.11
Pyrazoliumsalts react with dimethylphenylsilyl- and tert-butyldiphenylsilyllithium to give, in general, only one of the two possible 5-silyl-3-pyrazolines. On the other hand, indazolium and isoindazolium salts lead to 3-silylindazolines and occasionally to compounds resulting from the opening or expansion of the heterocyclic ring. All of these compounds are interesting synthons in organic chemistry
Reactions of Lithium Silylcuprates with Pyrazolium and Indazolium Salts
作者:Ana M. González-Nogal、Mariola Calle、Purificación Cuadrado
DOI:10.1002/ejoc.200700742
日期:2007.12
Although pyrazoliumsalts 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