A select route: By selecting the appropriate ligand, dihydrofurans and dihydrobenzoxepines can be chemoselectively formed in moderate to good yields with good to excellent diastereocontrol from identical starting materials (see scheme).
Preparation of Tetrasubstituted Furans via Intramolecular Wittig Reactions with Phosphorus Ylides as Intermediates
作者:Tzu-Ting Kao、Siang-en Syu、Yi-Wun Jhang、Wenwei Lin
DOI:10.1021/ol101080q
日期:2010.7.2
functional furans can be efficiently generated in one step at room temperature within 10 min to 21 h in moderate to high yields (60−99%). The reaction was proposed to proceed via intramolecular Wittig-type reactions, using phosphorus ylides as intermediates.
Highly Enantioselective Synthesis of Multifunctionalized Dihydrofurans by Copper-Catalyzed Asymmetric [4 + 1] Cycloadditions of α-Benzylidene-β-ketoester with Diazo Compound
Highly efficient synthesis of chiral tetrasubstituted 2,3-dihydrofuran derivatives has been realized by Cu-catalyzed asymmetric [4 + 1] cycloadditions of alpha-benzylidene-beta-ketoester with a diazo compound. Following this methodology, a series of optically active multifunctionalized dihydrofurans were prepared in high yield with up to 96% ee and 99/1 dr.
Thiourea catalysed reduction of α-keto substituted acrylate compounds using Hantzsch ester as a reducing agent in water
作者:Guanglin Weng、Xiaobo Ma、Dongmei Fang、Ping Tan、Lijiao Wang、Linlin Yang、Yuanyuan Zhang、Shan Qian、Zhouyu Wang
DOI:10.1039/c7ra00995j
日期:——
The first method for the reduction of α-keto substituted acrylate compounds by Hantzsch ester in water under the catalysis of thiourea has been developed. The products were isolated in moderate to high yields (38–95%). These products are important intermediates in the synthesis of a series of natural products and other biologically active molecules.