作者:G Bryon Gill、Muhammad S.Hj Idris
DOI:10.1016/s0040-4020(01)80521-4
日期:1993.1
prepared from their hydrates, respectively 3 and 4, by either chemical removal of the water (acetic anhydride in boiling acetic acid) or by azeotropic drying using chlorobenzene as solvent. The central CO groups of these triones are extremely electrophilic and ene addition occurs at these sites with a wide range of alkenes and with terminal alkynes in aprotic solvents at moderate temperatures (100–130°C)
分别由3和4的水合物制备四氧嘧啶1和1,3-二甲基四氧杂环己烷2都很方便。通过化学除去水(沸腾乙酸中的乙酸酐)或使用氯苯作为溶剂进行共沸干燥。这些三酮的中心CO基团具有极强的亲电性,并且在中等温度(100–130°C)下,质子惰性溶剂中的烯烃和加成末端均与烯烃种类繁多。所述烯加合物为5-烯丙基-5-羟基巴比妥酸或其N,N-二甲基类似物。立体选择性在相关时似乎主要由空间因素决定。但是,异戊二烯是通过Diels-Alder反应而不是通过烯加成反应。加合物是预期的区域异构体24。