π-Annulation reactions of 4-thiazolidinone enaminones in the synthesis of fused bi- and tri-cyclic compounds
作者:Bojan P. Bondžić、Zdravko Džambaski、Aleksandra M. Bondžić、Rade Marković
DOI:10.1016/j.tet.2012.09.080
日期:2012.11
reactivity of α-C of the exocyclic double bond (a so called push pull system) to obtain bicyclic fused thiazolidinones via π-annulation cyclization. Appropriate reaction conditions to selectively activate this position and secondary nitrogen towards N,π-annulation were found. Furthermore, the intramolecular vinylogous iminium ion 6-exo-trig cyclization was used to access fused bicyclic precursors for the
4-氧代噻唑烷酮中的α-C位置是这些分子中三个可能的亲核位点之一。我们利用环外双键(所谓的推挽系统)的α-C固有反应性,通过π-环化环化获得了双环稠合的噻唑烷酮。发现了适当的反应条件,以选择性地激活该位置和次氮向N,π-环化。此外,分子内的乙烯基亚胺鎓离子6- exo - trig环化被用于访问稠合的双环前体以进行π环化,以便立体选择性地获得新颖的三环结构。