Synthesis and Reactions of Silylated and Stannylated 1,2-Azoles
作者:Mariola Calle、Purificación Cuadrado、Ana M. González-Nogal、Raquel Valero
DOI:10.1055/s-2001-17699
日期:——
Silicon or tin 4-metalated pyrazoles and isoxazoles are synthesized by silyl- or stannylcupration from 4-haloazoles. On the other hand, 5-metalated pyrazoles are prepared by reaction of 5-unsubstituted pyrazoles with LDA and subsequent treatment with chlorosilanes and chlorostannanes. Furthermore, starting from 5-unsubstituted 4-halopyrazoles and applying both methodologies, 4,5-dimetalated pyrazoles bearing silyl groups different from trimethylsilyl or tributylstannyl groups are obtained. Some regioselective ipso-substitutions are also studied.
Silylated azolium salts and their applications in the synthesis of azolines and β-enaminoketones bearing allyl-, vinyl-, and acylsilane or α-silylketone units
作者:Ana M. González-Nogal、Mariola Calle
DOI:10.1016/j.tet.2009.01.114
日期:2009.7
Differently silylated 3- or 4-isoxazolines and 3-pyrazolines, bearing versatile vinyl- or allylsilane moieties in various positions of the heterocyclic system, have been synthesized starting from new silylazolium salts by reduction with metal complex hydrides or alkylation with organolithium reagents. On the other hand, the reductive ring-opening of silylated isoxazolium salts with lithium dimethylcuprate