Generation and spectroscopic characterization of ruthenacyclobutane and ruthenium olefin carbene intermediates relevant to ring closing metathesis catalysis
Generation and spectroscopic characterization of ruthenacyclobutane and ruthenium olefin carbene intermediates relevant to ring closing metathesis catalysis
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DOI：
10.1021/ja710364e
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发表时间：
2008-04-02
影响因子：
15
通讯作者：
Piers, Warren E.
中科院分区：
文献类型：
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作者：
van der Eide, Edwin F.;Romero, Patricio E.;Piers, Warren E.
亚烷基膦[(H(2)LMES)RuCl2=CHPR3](+)[A](-)(R=C6H11，A=OTf或B(C6F5)4，1-Cy；R=I-C3H7，A=CIB(C6F5)(3)或OTf，1-‘Pr)与1当量乙烯在-78℃反应，在2-3当量的烯烃底物存在下，生成与烯烃歧化催化循环有关的中间体。环戊烷-3-烯-1，1-二羧酸二甲酯给出了与闭环歧化催化有关的取代苯环丁烷3的溶液。H-1和C-13的核磁共振数据与其为苯环丁烷的归属完全一致，但(1)CαH2-C-β键的JCC值为23 Hz，CαH-C-β键的JCC值为8.5 Hz，表明CαH-C-β键比前者更活跃。与之相反，用萘捕获导致了一个烯烃卡宾络合物(6)，其中假定的苯环丁烷已经打开；这个物种也被核磁共振光谱完全表征，并与以前报道的相关物种进行了比较。
The reaction of phosphonium alkylidenes [(H(2)lMes)RUCl2=CHPR3](+)[A](-) (R = C6H11, A = OTf or B(C6F5)4, 1-Cy; R = i-C3H7, A = CIB(C6F5)(3) or OTf, 1-'Pr) with 1 equiv of ethylene at -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. H-1 and C-13 NMR data are fully consistent with its assignment as a ruthenacyclobutane, but (1)Jcc values of 23 Hz for the C alpha H2-C-beta bond and 8.5 Hz for the C alpha H-C-beta bond point to an unsymmetrical structure in which the latter bond is more activated than the former. In contrast, trapping with acenaphthylene leads to an olefin carbene complex (6) in which the putative ruthenacyclobutane has opened; this species was also fully characterized by NMR spectroscopy and compared to related species reported previously.