A novel application of 2-silylated 1,3-dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes
作者:Grzegorz Mlostoń、Paulina Pipiak、Róża Hamera-Fałdyga、Heinz Heimgartner
DOI:10.3762/bjoc.13.185
日期:——
regioselectivity by aryl or hetaryl thioketones forming also sterically crowded 2-trimethylsilyl-1,3-dithiolanes. The obtained 1,3-dithiolanes, by treatment with an equimolar amount of TBAF in a one-pot procedure, are converted in high yields into hetaryl/aryl-substituted ethenes or dibenzofulvenes, respectively, via a cycloreversion reaction of the intermediate 1,3-dithiolane carbanion. The presented protocol
三甲基甲硅烷基重氮甲烷(TMS-CHN2)与杂芳基硫酮容易反应,在-75°C和rt下具有完全区域选择性的空间拥挤的2-trimethylsilyl-4,4,5,5-tetrahetaryl-1,3-dithiolanes。硫芴酮是一种相对稳定和高反应性的芳基硫代酮,在-60°C下用TMS-CHN2处理后,生成相应的1,3,4-噻二唑啉。该不稳定的环加合物在约200℃下分解。在-45℃下,由此产生的甲硅烷基化的硫代羰基S-甲烷被完全芳基选择性地被芳基或杂芳基硫酮捕获,从而形成空间上拥挤的2-三甲基甲硅烷基-1,3-二硫杂环戊烷。通过一锅法用等摩尔量的TBAF处理获得的1,3-二硫杂环戊烷,分别以高收率转化成杂芳基/芳基取代的乙烯或二苯并富勒烯,通过中间体1,3-二硫代碳负离子的环还原反应。提出的协议为带有芳基和/或杂芳基取代基的四取代乙烯和二苯并富烯提供了一种高效的新方法。