Transition Metal-Mediated Intramolecular [2+2+2] Cycloisomerizations of Cyclic Triynes and Enediynes

Nitrogen-containing 15-membered triacetylenic macrocycles known as 1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-triynes (1) and enediynic macrocycles called 1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3-ene-8,13-diynes (4 and 5) were satisfactorily prepared. [2+2+2]
cycloisomerization processes catalyzed by transition metals were tested in the above-mentioned
macrocycles. Readily available and familiar cyclotrimerization precatalysts were examined for
efficiency. Among them, the RhCl(CO)(PPh3)2 complex was found to catalyze the cycloisomerization
reaction giving the desired cycloadducts in high yields.

含氮15元三炔大环（即1,6,11-三(芳磺酰基)-1,6,11-三氮杂环十五烷-3,8,13-三炔，编号1）与烯二炔大环（即1,6,11-三(芳磺酰基)-1,6,11-三氮杂环十五烷-3-烯-8,13-二炔，编号4和5）已被成功制备。研究以过渡金属催化的[2+2+2]环异构化（cycloisomerization）反应对上述大环化合物进行了测试，同时考察了多种易得且常用的环三聚（cyclotrimerization）预催化剂的催化效率。其中，RhCl(CO)(PPh3)2配合物被证实可催化该环异构化反应，以高收率得到目标环加成产物。