Sulfuric-acid-promoted tandem reaction of phenols with acetophenones under solvent- and metal-free conditions has been developed, which afforded functional 4H-chromenes in good yields with water as the side product.
Efficient Synthesis of Functionalized 4H-Chromenes via an Fe(OTf)3-Catalyzed Cyclization Reaction of Phenols and Ketones
作者:Hui-Jing Li、Yan-Chao Wu、Kai Deng、Qi-Yong Huai、Jun-Hu Wang、Hui-Ru Yang、Ying Liu
DOI:10.1055/s-0036-1591021
日期:2018.4
Abstract The iron(III) triflate catalyzed cyclization reaction of phenols and ketones is described; the reaction provides a direct approach to 4H-chromene derivatives. 4H-Chromene is an important structural fragment of many pharmaceuticals, natural products, and functional materials. The 4H-chromene synthetic protocol possesses many advantages, such as using readily available and inexpensive starting
ABSTRACT: A domino one‐pot synthesis of 2H‐chromenes and 4H‐chromenes starting from phenols and terminal acetylenes under solvent‐free and atom economy conditions, is described. This annulation reaction between phenols with alkynes, is promoted by simple Lewis acid ZnCl2. Significantly, to the best of our knowledge, the synthesis of 2H‐chromenes, is first of its kind, particularly, using terminal alkyl
An efficient and highlyselective approach for the synthesis of functionalized 4H-chromenes has been developed via gold(III)-catalyzed condensation/annulation tandem reaction of ketones with phenols.
A simple Lewis acid induced reaction of phenols with electrophiles: Synthesis of functionalized 4<i>H</i>-chromenes and <i>ortho</i>-benzylphenols
作者:Chinnabattigalla Sreenivasulu、Ditto Abraham Thadathil、Sumit Pal、Satyanarayana Gedu
DOI:10.1080/00397911.2019.1689268
日期:2020.1.2
Abstract Lewisacid ZnCl2 promoted cyclization protocol to 4H-chromenes is accomplished, using readily available phenols and acetophenones as starting materials. Interestingly, the process is feasible under the solvent free environment. Synthesis of a variety of 4H-chromenes have been accomplished using this strategy. In addition, this concept is extended to the synthesis of ortho-benzylphenols by