Protection of the carbonyl groups in 1,2-indanedione: propellane versus acetal formation
作者:Joseph Almog、Nikolay Stepanov、Faina Dubnikova
DOI:10.1016/j.tetlet.2008.01.012
日期:2008.3
The product resulting from the reaction between 1,2-indanedione and ethylene glycol under acidic catalysis is 2,5,7,10-tetraoxapropellane and not 1,2-dispirane as previously reported. Similar reactions also occur with 2-mercaptoethanol and 1,2-ethanedithiol, which form analogous propellanes and not corresponding thioacetals. This explains the difficulty of removing the protective groups under acidic
1,2-茚满二酮和乙二醇在酸性催化下反应生成的产物是2,5,7,10-四氧杂丙烷,而不是先前报道的1,2-二螺烷。用2-巯基乙醇和1,2-乙二硫醇也发生类似的反应,它们形成类似的丙炔而不是相应的硫缩醛。这解释了在酸性条件下除去保护基的困难。量子化学计算证实了这些发现。在相似的条件下,即使使用3倍过量的二醇,长链二醇1,3-丙二醇及其硫醇类似物1,3-丙二酚也仅形成单缩醛。然而,亲核攻击发生在不同的位置:丙泛醇在c-1处形成乙缩醛,丙二醇在c-2处形成乙缩醛。