Reactivity of pyridines bearing EWG with bis-(TMS)ketene acetals. Substituent-induced lactonization reaction
作者:Alejandro Rivera-Hernández、Guillermo M. Chans、Henri Rudler、José G. López Cortés、R. Alfredo Toscano、Cecilio Álvarez-Toledano
DOI:10.1016/j.tet.2014.01.044
日期:2014.3
The nucleophilic addition of bis-(TMS)ketene acetals to pyridines substituted by electron-withdrawing groups, activated with triflicanhydride, leads to their corresponding dihydropyridine carboxylic acids in a first instance. These acids can be efficiently turned into new bicyclic lactones by either of three different methods: first, bicyclic γ-lactones were successfully obtained by an unprecedented