An efficient synthetic method was developed for the selective construction of 2H-chromene derivatives from various salicylaldehydes and acetylenic diesters using a dual catalyst system (p-toluenesulfonic acid monohydrate and pyrrolidine). The advantages of this transformation include high selectivity, good functional group tolerance, operational simplicity, and mild reaction conditions.
Construction of Diverse and Functionalized 2<i>H</i>-Chromenes by Organocatalytic Multicomponent Reactions
作者:Hongyun Cai、Likai Xia、Yong Rok Lee、Jae-Jin Shim、Sung Hong Kim
DOI:10.1002/ejoc.201500616
日期:2015.8
A green and efficient one-pot process for the construction of diverse and functionalized 2H-chromenes was developed by usingmulticomponentreactions of salicylaldehydes, alkynes (i.e., propiolate and acetylenedicarboxylates), and alcohols. This new protocol was achieved by using L-proline as a mild and green organocatalyst and offers several advantages such as economic availability, low toxicity,
Microwave assisted synthesis of hydroxychromenes using imidazole-functionalized silica nanoparticles as a catalyst under solvent-free conditions
作者:Hassan Valizadeh、Leila Dinparast、Saeideh Noorshargh、Majid M. Heravi
DOI:10.1016/j.crci.2015.11.010
日期:2016.3
Résumé A microwave-assisted reaction of various salicylaldehydes with dialkyl acetylenedicarboxylates mediated by imidazole-functionalized silica nanoparticles is successfully and rapidly achieved to afford the corresponding hydroxychromenes in high to excellent yields under solvent-free conditions.