Novel <i>Z</i>-Selective Head-to-Head Dimerization of Terminal Alkynes Catalyzed by Lanthanide Half-Metallocene Complexes
作者:Masayoshi Nishiura、Zhaomin Hou、Yasuo Wakatsuki、Taeko Yamaki、Takeshi Miyamoto
DOI:10.1021/ja027595d
日期:2003.2.1
the reaction. Therefore, this catalyst system works homogeneously but can be separated and reused, thus constituting the first example of a recyclable catalyst system for the dimerization of terminal alkynes and also the first example of (Z)-selective head-to-head dimerization of aromatic terminal alkynes.
通过使用半茂金属镥烷基配合物 Me2Si(C5Me4)(NAr)Lu(CH2SiMe3)(THF) (Ar = Ph, C6H3Me2 -2,6, C6H2Me3-2,4,6) 作为催化剂。众所周知,芳香族 C-Cl、C-Br 和 CI 键极易受到过渡金属的还原裂解,但在本反应中幸存下来。相应的二聚炔化物 [Me2Si(C5Me4)(NAr)Lu(mu-CCR)]2 被认为是真正的催化剂,其中一些已被分离并进行结构表征。这些炔化物物质在反应温度(80-110 摄氏度)下是热稳定的并且可溶,但它们在反应完成后冷却至室温时会沉淀。因此,该催化剂体系工作均匀,但可以分离和重复使用,