A Simple and Efficient Synthesis of Heterocycle-Fused 2<i>H</i>-Thiopyrans, Furo-, Benzofuro-, Thieno-, Benzothieno-, Pyrrolo- and Indolo-2<i>H</i>- thiopyrans, from Heteroaromatic Thioketones and α-Chloroacrylonitrile or α-Bromoacrylic Esters via a Hetero Diels-Alder Reaction-Dehydrohalogenation Process
An efficient and convenient procedure is described for the synthesis of heterocycle-fused 2H-thiopyrans having ortho-dimethylene structures via a hetero Diels-Alder reaction-dehydrohalogenation process starting from heteroaromatic thioketones and α-chloro-acrylonitrile or α-bromoacrylates.
CYCLOADDITION REACTIONS OF ARYL 2-FURYL THIONES AND ARYL 2-THIENYL THIONES WITH MALEIC ANHYDRIDE AND 2-NORBORNENE
作者:Haruo Ohmura、Shinichi Motoki
DOI:10.1246/cl.1981.235
日期:1981.2.5
The reactions of aryl 2-furyl thiones with maleic anhydride and 2-norbornene gave 1,4-cycloadducts. The reactions of aryl 2-thienyl thiones with maleic anhydride gave aromatized and oxidized 1,4-cycloadducts, while the reaction with 2-norbornene gave only normal 1,4-cycloadducts. In these reactions, one of the double bond in the furan or thiophene ring and the thiocarbonyl group reacted as a hetero