Polylithiumorganic compounds — 23. 3,4-Dilithio-1,2-butadienes by addition of lithium metal to 1,4-unsymmetrically substituted butatrienes
作者:Adalbert Maercker、Hans Wunderlich、Ulrich Girreser
DOI:10.1016/0040-4020(96)00235-9
日期:1996.4
The synthesis of the highly reactive 1,4-unsymmetrically substituted butatrienes 12a-c is described. When employing a strict synthetic protocol, these alkatrienes react with lithium metal to 3,4-dilithio-1,2-butadienes 20a-c as stable intermediates. The structure of 20 is supported by IR and NMR spectroscopic evidence. The same dianionic intermediate can be prepared in one case by double deprotonation
描述了高反应性的1,4-不对称取代的丁烯12a-c的合成。当采用严格的合成方案时,这些链烷烃与锂金属反应生成3,4-二硫代-1,2-丁二烯20a-c,作为稳定的中间体。20的结构得到IR和NMR光谱证据的支持。在一种情况下,可以通过1,2-丁二烯19的双重去质子化反应来制备相同的双阴离子中间体。一旦衍生化,或者3,4-二取代的1,2-丁二烯24,2,3-二取代的1,3-丁二烯25,或1,4-二取代-2-丁炔26被形成,这取决于所用的亲电子试剂的性质。