Brønsted acid-promoted cyclizations of siloxy alkynes with unactivated arenes, alkenes, and alkynes
作者:Liming Zhang、Jianwei Sun、Sergey A. Kozmin
DOI:10.1016/j.tet.2006.06.037
日期:2006.12
found that trifluoromethane sulfonimide (HNTf2) proved to be a superior promoter of these reactions compared to a range of other Brønsted acids. This finding could be attributed to a high acidity of HNTf2 in aprotic organic solvents combined with a low nucleophilicity of the NTf2− anion. Depending on the nature of the nucleophile, the carbocyclizations proceeded either via 6-endo-dig or 5-endo-dig manifolds
在本文中,我们描述了开发新的碳-碳键形成过程的一般概念,该概念基于布朗斯台德酸介导的甲硅烷氧基炔烃的活化作用,然后有效截获所得的高反应性离子通过未活化的芳烃,烯烃或炔烃。我们发现,与一系列其他布朗斯台德酸相比,三氟甲烷磺酰亚胺(HNTf 2)被证明是这些反应的优良促进剂。这一发现可以归因于HNTf的高酸度2与所述NTF的低亲核性组合非质子有机溶剂2 -阴离子。根据亲核试剂的性质,碳环化可通过6-endo-dig或5个内挖式歧管。在1-甲硅烷基-1,5-二炔的情况下,环化反应伴随着卤化物的抽象或芳基化。