Organocatalysis of nucleophilic substitution reactions by the combined effects of two promoters fused in a molecule: oligoethylene glycol substituted imidazolium salts
作者:Vinod H. Jadhav、Ju-Young Kim、Dae Yoon Chi、Sungyul Lee、Dong Wook Kim
DOI:10.1016/j.tet.2013.10.070
日期:2014.1
Oligoethylene glycol substituted imidazolium salts were synthesized as promoters for a range of SN2 reactions, and their efficiency was examined. These tailor-made organic promoters enhanced the nucleophilicity of alkali metal salts significantly through the combined effects of two promoters (oligoethylene glycols and imidazolium salts) in a single molecule. The effects of the oligoethylene glycol
合成了低聚乙二醇取代的咪唑鎓盐作为一系列S N 2反应的促进剂,并检查了它们的效率。这些量身定制的有机促进剂通过两个促进剂(低聚乙二醇和咪唑鎓盐)在单个分子中的联合作用,显着增强了碱金属盐的亲核性。系统研究了低聚乙二醇侧链长度,离子液体阴离子,亲核试剂和底物的影响。[hexaEGmim] [OMs]和[dihexaEGim] [OMs]显示了使用碱金属盐进行S N 2反应的最高效率。通过检查相对S N来评估低聚乙二醇部分的末端羟基基团的作用2氯化和溴化收率。结果表明,羟基与亲核试剂的氢键强度非常重要。通过量子化学计算研究了oligoEGILs促进S N 2反应的优异机理。结果表明,低聚乙二醇部分中的氧原子和离子液体阴离子作为路易斯碱作用于抗衡阳离子K +或Na +上,从而显着提高了金属盐的反应性。