Boronic acid/Brønsted acid co-catalyst systems for the synthesis of 2H-chromenes from phenols and α,β-unsaturated carbonyls
作者:Victoria Dimakos、Tishaan Singh、Mark S. Taylor
DOI:10.1039/c6ob01026a
日期:——
Protocols for the synthesis of substituted 2H-chromenes from α,β-unsaturated carbonyls and phenols are described. Optimal combinations of arylboronic acids and Brønsted acids have been identified, such that both can be employed in catalytic quantities to accelerate these condensations. The method has been used to synthesize a variety of substituted 2H-chromenes, as well as photochromic naphthopyrans
A Quick, Clean and Green Synthesis of Methylenedioxyprecocene and other Chromenes over Basic Montmorillonite K10 Clay
作者:Matthew R. Dintzner、Thomas W. Lyons、Michael H. Akroush、Paul Wucka、Adam T. Rzepka
DOI:10.1055/s-2005-863738
日期:——
The microwave-assisted, clay-catalyzed condensation of sesamol and other phenols with 3-methyl-2-butenal to give methylenedioxyprecocene 3 and other chromenes, is described.
Synthesis of New (±) Pterocarpans by Heck Oxyarylation
作者:S. Sa e Sant'Anna、E. A. Evangelista、R. B. Alves、D. S. Raslan
DOI:10.1007/s10600-005-0158-z
日期:2005.7
Among a wide variety of synthetic routes to pterocarpan prototypes, a mild approach uses a reaction known as Heck oxyarylation. This method involves a reaction between 2H-chromenes and 2-chloromercuriophenols in the presence of Li2PdCl4.
Fast [3+2] Cycloaddition Synthesis of (±) Pterocarpans under Microwave Irradiation
作者:Claiton P. Ventura、Iara Maira de O. Viana、Eruzia A.E. Ferreira、Rossimiriam P. de Freitas、Rosemeire B. Alves
DOI:10.2174/157017810791514896
日期:2010.7.1
Herein we describe a method for the fast cycloaddition reaction of 2H-chromenes with 2-methoxy-1,4- benzoquinones by microwave heating. Using this methodology we have synthesised seven pterocarpans derivatives, five of which are novel compounds. Microwave heating allows significant yield enhancements and reduction of reaction time when compared to traditional methodology.