Synthesis of thiophenes from allenyl sulfones involving α,β-unsaturated sulfines as intermediates
作者:Johannes B. van der Linden、Peter F. T. M. van Asten、Samuel Braverman、Binne Zwanenburg
DOI:10.1002/recl.19951140203
日期:——
The synthesis of thiophenes starting from allenyl sulfones, via intermediate formation of α,β-unsaturated sulfines, is described. The allenyl sulfones were synthesized by a [2,3]-sigmatropic rearrangement of appropriately substituted prop-2-ynyl sulfinates. Treatment of the allenyl sulfones with n-butyllithium and chlorotrimethylsilane gave α-silylated allenyl sulfones in almost quantitative yield
描述了通过α,β-不饱和亚砜的中间形成,从烯丙基砜开始的噻吩的合成。通过适当取代的丙-2-炔丙基亚磺酸酯的[2,3]-σ重排合成了烯丙基砜。用正丁基锂和三甲基氯硅烷处理烯丙基砜,可以几乎定量地得到α-甲硅烷基化的烯丙基砜,在有机共轭试剂的杂共轭加成中,得到所需的α-甲硅烷基碳负离子。它们与二氧化硫反应生成α,β-不饱和亚砜,将其原位进行重排为2-磺酰基噻吩。噻吩的产率取决于所用的有机锂试剂。外环烯基砜的使用更麻烦,仅一个实例就获得了噻吩。