Generation and Spectroscopic Characterization of Ruthenacyclobutane and Ruthenium Olefin Carbene Intermediates Relevant to Ring Closing Metathesis Catalysis
作者:Edwin F. van der Eide、Patricio E. Romero、Warren E. Piers
DOI:10.1021/ja710364e
日期:2008.4.1
-78 degrees C, in the presence of 2-3 equiv of a trapping olefin substrate, yields intermediates relevant to olefin metathesis catalytic cycles. Dimethyl cyclopent-3-ene-1,1-dicarboxylate gives solutions of a substituted ruthenacyclobutane 3 of relevance to ring closing metathesis catalysis. 1H and 13C NMR data are fully consistent with its assignment as a ruthenacyclobutane, but 1JCC values of 23
鏻亚烷基的反应[(H2IMes)RuCl2=CHPR3]+[A]-(R = C6H11, A = OTf or B(C6F5)4, 1-Cy; R = i-C3H7, A = ClB(C6F5)3或 OTf, 1-iPr) 与 1 当量的乙烯在 -78 摄氏度下,在 2-3 当量的捕集烯烃底物存在下,产生与烯烃复分解催化循环相关的中间体。Dimethyl cyclopent-3-ene-1,1-dicarboxylate 提供了与闭环复分解催化相关的取代钌环丁烷 3 的溶液。1H 和 13C NMR 数据与其作为钌环丁烷的指定完全一致,但 CalphaH2-Cbeta 键的 1JCC 值 23 Hz 和 CalphaH-Cbeta 键的 8.5 Hz 指向不对称结构,其中后一个键比前者。相比之下,用苊捕获生成烯烃卡宾配合物 (6),其中假定的钌环丁烷已打开;该物种还通过核磁共振光谱进行了充