[4+2] cycloaddition of intermediates generated from arynes and DMF
作者:Eito Yoshioka、Hirofumi Tamenaga、Hideto Miyabe
DOI:10.1016/j.tetlet.2013.12.119
日期:2014.2
The trappingreaction of the transient intermediateortho-quinone methides, generated by the insertion of arynes into a carbon–oxygen double bond of DMF, with dienophiles was investigated. The [4+2] cycloaddition products were obtained when the diesters of acetylenedicarboxylic acid were employed as dienophiles.
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.
Reaction between <i>ortho</i>‐Hydroxy Aromatic Aldehydes and Dialkyl Acetylenedicarboxylates in the Presence of Silica Gel in Solvent‐Free Conditions
作者:Nader Noshiranzadeh、Ali Ramazani
DOI:10.1080/00397910701545486
日期:2007.9.1
Abstract A two‐component condensation reaction between an ortho‐hydroxy aromatic aldehyde and an electron‐poor acetylenic ester efficiently provides fully substituted electron‐poor aryl vinyl ethers and chromenes in a one‐pot reaction in the presence of silica‐gel in solvent‐free conditions.