α,β-Unsaturated thiocarbonyl S-sulfides (thiosulfines)10 were generated by sulfurization of the thioketones 5 and were intramolecularly trapped as 1,5-dipoles giving 8, whereas, in the presence of Et3N, they were transformed by trans-sulfurization via 1,5 cyclization into the thioketones 13 capable of undergoing the intramolecular hetero-DielsâAlder reaction to give cycloadducts 9.
δ,δ²-不饱和
硫代羰基 S-
硫化物(
硫代
硫化物)10 是通过
硫化
硫酮 5 生成的,并以 1,5 二极的形式在分子内截留,得到 8,而在 Et3N 存在的情况下,它们通过 1,5 环化反式
硫化转变为
硫酮 13,并能发生分子内杂-DielsâAlder 反应,得到环加成物 9。