Stereoselective hetero-Diels–Alder reaction of 3-nitro-2-trihalomethyl-2H-chromenes with 2,3-dihydrofuran and ethyl vinyl ether under solvent-free conditions
作者:Vladislav Yu. Korotaev、Vyacheslav Ya. Sosnovskikh、Mikhail A. Barabanov、Evgeniya S. Yasnova、Marina A. Ezhikova、Mikhail I. Kodess、Pavel A. Slepukhin
DOI:10.1016/j.tet.2009.11.094
日期:2010.2
3-Nitro-2-trifluoro(trichloro)methyl-2H-chromenes undergo heterodiene cycloaddition to 2,3-dihydrofuran and ethyl vinyl ether under solvent-free conditions producing novel cyclic nitronates with high stereoselectivity and in good yields. 3,6-Dinitro-2-trifluoromethyl-2H-chromene reacts with two molecules of ethyl vinyl ether to give the tandem [4+2]/[3+2] cycloaddition adduct in 48% yield. The stereochemistry of the products
3-硝基-2-三氟(三氯)甲基-2 H-色烯在无溶剂条件下经历异二烯环加成反应生成2,3-二氢呋喃和乙基乙烯基醚,从而以高立体选择性和高收率生产出新型环状硝酸盐。3,6-二硝基-2-三氟甲基-2 H-色烯与两个分子的乙基乙烯基醚反应,以48%的收率得到串联的[4 + 2] / [3 + 2]环加成产物。产品的立体化学是根据2D COSY,NOESY,HSQC和HMBC实验以及X射线衍射研究确定的。