Formation of Allenyl Ketones, 3-Ethynylcoumarins, and Arylfurans, Furylfurans, and Furylthiophenes by Flash Vacuum Thermolysis of 3-Methylidenefuran-2(3<i>H</i>)-ones
作者:Rainer Koch、Hans Michael Berstermann、Curt Wentrup
DOI:10.1021/jo402139a
日期:2014.1.3
Flash vacuum thermolysis (FVT) of 3-methylidenefuran-2(3H)-ones 3 causes cheletropic extrusion of CO with formation of allenyl ketones 4. o-Chloro- and o-bromophenylmethylidenefuranones also afford allenyl ketones upon flash vacuum thermolysis, but in addition, 3-ethynylcoumarins 6 are formed via E/Z isomerization of the methylidenefuranones, cyclization, halogen atom migration, and HCl (HBr) elimination
3- methylidenefuran-2(3闪热解真空(FVT)ħ) -酮3倍的原因的CO cheletropic挤出与地层丙二烯基酮4。Ò氯代和ö -bromophenylmethylidenefuranones也得到在闪速热解真空丙二烯基酮,但除此之外,3- ethynylcoumarins 6经由形成é / Ž的methylidenefuranones,环化,卤素原子迁移,和HCl(HBR)消除异构化。酰基丙二烯部分上存在强吸电子基团(硝基芳基或乙酰基)会引起重排,从而生成2-芳基呋喃10和13以及通过烯基酮的环化作用的2-呋喃呋喃和2-呋喃噻吩16。在M06-2X / 6-311 + G(d,p)的理论水平上的计算为反应机理提供了支持。