ACYCLIC CP(CO)2FE DISUBSTITUTED ETA-1-VINYLIDENE-ETA-2-ACETYLENE ISOMERIZATIONS
ACYCLIC CP(CO)2FE DISUBSTITUTED ETA-1-VINYLIDENE-ETA-2-ACETYLENE ISOMERIZATIONS
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DOI：
10.1021/om00015a024
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发表时间：
1994-03-01
期刊：
影响因子：
2.8
通讯作者：
BLY, RK
中科院分区：
文献类型：
--
作者：
BLY, RS;ZHONG, ZD;BLY, RK
无环的二取代亚乙烯基络合物[Cp（CO）2 Fe =C= CR 1 R 2]+TfO-，3a-c（a，R1，R2 = Me; B，R1 = Ph，R2 = Me; c，R1，R2 = Ph）在高于-50 ℃的CD 2 Cl 2中异构化为非末端乙炔络合物[CP（CO）2 Fe（eta 2-R1-C=C-R2）]+TfO-，5a-c。碳-13标记和VT 13 C NMR用于追踪3的形成及其转化为5。异构化是分子内的，并且显然是不可逆的。3b至5 b的迁移仅涉及苯基迁移。这表明，Cp（CO）2Fe eta 2-乙炔是有利的CP（CO）2Fe eta 1-亚乙烯基在这些条件下的强吸电子的CO，相对于较少的π-酸性配体，不稳定的亚乙烯基和稳定的π-乙炔。
Acyclic, disubstituted vinylidene complexes, [Cp(CO)2Fe=C=CR1R2]+TfO-, 3a-c (a, R1, R2 = Me; b, R1 = Ph, R 2 = Me; c, R1, R2 = Ph), isomerize to nonterminal -acetylene complexes, [CP(CO)2Fe(eta2-R1-C=C-R2)]+TfO-, 5a-c, in CD2Cl2 above -50-degrees-C. Carbon-13 labeling and VT 13C NMR are used to track the formation of 3 and its conversion to 5. The isomerizations are intramolecular and apparently irreversible. That of 3b to 5b involves only phenyl migration. It is suggested that Cp(CO)2Fe eta2-acetylenes are favored over CP(CO)2Fe eta1-vinylidenes under these conditions by the strongly electron withdrawing COs which, relative to less pi-acidic ligands, destabilize the vinylidene and stabilize the pi-acetylene.