Additive-Controlled Switchable Selectivity from Cyanobenzenes to 2-Alkynylpyridines: Ruthenium(II)-Catalyzed [2+2+2] Cycloadditions of Diynes and Alkynylnitriles
Additive-Controlled Switchable Selectivity from Cyanobenzenes to 2-Alkynylpyridines: Ruthenium(II)-Catalyzed [2+2+2] Cycloadditions of Diynes and Alkynylnitriles
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DOI：
10.1002/adsc.201800228
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发表时间：
2018-05-02
影响因子：
5.4
通讯作者：
Goswami, Avijit
中科院分区：
文献类型：
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作者：
Bhatt, Divya;Patel, Neha;Goswami, Avijit
在二甲氧基乙烷(DME)中，以氯代(五甲基环戊二烯)(环辛二炔)Ru(II)为催化剂，1，6-二炔与炔基腈反应，建立了一种高效的添加剂依赖的化学选择性合成稠合氰基芳烃和2-炔基吡啶的方法。只需添加催化量的AgOTf作为添加剂，就可以彻底改变反应过程，从而使产物的生成从氰基芳烃全面转变为2-炔基吡啶。理论研究清楚地表明，中性Ru-络合物是氰基苯形成的原因，而原位生成的阳离子Ru-络合物在2-炔基吡啶的形成中起着至关重要的作用。
A highly efficient additive-dependent chemoselective protocol for the synthesis of fused cyanoarenes and 2-alkynylpyridines has been developed by the reaction of 1,6-diynes with alkynylnitriles using chloro(pentamethylcyclopentadienyl) (cyclooctadiyne) ruthenium(II) as catalyst in dimethoxyethane (DME). The course of the reaction can be drastically altered simply by adding a catalytic amount of AgOTf as an additive resulting in a comprehensive shift in product formation from cyanoarenes to 2-alkynylpyridines. Theoretical studies clearly indicate that the neutral Ru-complex is responsible for the formation of cyanobenzenes, whereas the in situ generated cationic Ru-complex plays a crucial role in the 2-alkynylpyridines formation.