Intramolecular hetero-Diels–Alder reaction of 1-oxa-1,3-butadienes with terminal acetylenes in aqueous media using CuI
摘要:
A new method for the preparation of tetracyclic uracils (oxa-helicene) 4 was developed. The intramolecular hetero-Diels-Alder reaction of 1-oxa-1,3-butadiene 3 and an unactivated alkyne in the presence of CuI led to tetracyclic uracils 4 in aqueous media with good yields. The 1-oxa-1,3-butadiene 3 was prepared through Knoevenagel reaction of O-propargylated salicylaldehyde derivatives and barbituric acid or 1,3-dimethylbarbituric acid. (C) 2008 Published by Elsevier Ltd.
Zirconium oxide (NP) - ionic liquid as an efficient media for the domino Knoevenagel hetero Diels-Alder reaction with unactivated alkynes
作者:Saeed Balalaie、Ali Poursaeed、Malihe Javan Khoshkholgh、Hamid Reza Bijanzadeh、Eckardt Wolf
DOI:10.1016/j.crci.2011.12.002
日期:2012.4
Immobilized ZrO 2 -nanopowder (NP) in ionic liquid and different organic solvents was used as a suitable Lewis-acid for the synthesis of polycyclic heterocycles which contains pyran-based skeletons. Reaction of O -propargylated salicylaldehyde with activemethylenecompounds in the presence of ZrO 2 -NP in ionic liquid proceeds via domino Knoevenagel hetero Diels-Alder reaction of unactivated alkynes
CuI–Ionic Liquids as Efficient Reaction Media for the Synthesis of Pyran Skeleton via Domino Knoevenagel–Hetero–Diels–Alder Reaction with Unactivated Alkynes
Abstract The article describes ionic liquids [bmim][NO3] in the presence of 30% mol CuI as efficient media for the domino Knoevenagel–hetero–Diels–Alder reaction of o-propargyloxy benzaldehydes as unactivated terminal alkynes with some active methylene compounds. Short reaction time, easy workup, good to excellent yields, and mild conditions are advantages of this new media. Supplemental materials
A new method for the preparation of tetracyclic uracils (oxa-helicene) 4 was developed. The intramolecular hetero-Diels-Alder reaction of 1-oxa-1,3-butadiene 3 and an unactivated alkyne in the presence of CuI led to tetracyclic uracils 4 in aqueous media with good yields. The 1-oxa-1,3-butadiene 3 was prepared through Knoevenagel reaction of O-propargylated salicylaldehyde derivatives and barbituric acid or 1,3-dimethylbarbituric acid. (C) 2008 Published by Elsevier Ltd.