Alkyne-Isocyanide Coupling in [Fe2(CNMe)(CO)3(Cp)2]: A New Route to Diiron -Vinyliminium Complexes
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- 作者：Vincenzo G. Albano ; Luigi Busetto ; Fabio Marchetti ; Magda Monari ; Stefano Zacchini ; Valerio Zanotti
- 刊名：Organometallics
- 出版年：2007
- 出版时间：July 2, 2007
- 年：2007
- 卷：26
- 期：14
- 页码：3448 - 3455
- 全文大小：199K
- 年卷期：v.26,no.14(July 2, 2007)
- ISSN：1520-6041
文摘
Alkynes (RC
CR') insert into the metal-isocyanide bond of [Fe2(CNMe)(CO)3(Cp)2] (1), under UVirradiation, affording the complexes [Fe2{
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1:3-C(R)C(R')C=N(Me)}(-CO)(CO)(Cp)2] (R = R'= Ph,2a; R = R' = Me, 2b; R = R' = Et, 2c; R = Ph, R' = H, 2d; R = Tol, R' = H, 2e; R = SiMe3, R' =H, 2f; R = Me, R' = H, 2g; R = CH2OH, R' = H, 2h; Tol = 4-MeC6H4), with displacement of one COligand. Compounds 2b,c exist as a mixture of cis and trans isomers (with reference to the mutual Cpposition), whereas 2a,d-h exclusively have the cis geometry. The insertion of terminal alkynes isregioselective, since C-C bond formation occurs selectively between the isocyanide and the nonsubstitutedcarbon of HCCR. Compound 1 reacts with 2 equiv of HCCCO2Me under UV irradiation, affording[Fe2{-2:4-C(OH)C(CO2Me)C(H)CN(Me)(CH=CHCO2Me}(CO)(Cp)2] (4). Complexes 2a,c undergoelectrophilic addition at the N atom by treatment with HSO3CF3, allyl iodide (ICH2CH=CH2), and methylchloroformate (ClCOOMe), affording the corresponding vinyliminium cations [Fe2{-1:3-C(R)=C(R)C=N(Me)(E)}(-CO)(CO)(Cp)2]+ (R = Ph, E = H, 5a; R = Et, E = H, 5b; R = Ph, E = CH2CH=CH2,6; R = Ph, E = CO2Me, 7). The reactions of 6 with NaBH4 and NBu4CN afford [Fe2{-1:3-C(Ph)C(Ph)=C(H)N(Me)(CH2CH=CH2)}(-CO)(CO)(Cp)2] (8) and [Fe2{-1:3-C(Ph)C(Ph)C(CN)N(Me)(CH2CH=CH2)}(-CO)(CO)(Cp)2] (9), respectively. The molecular structures of cis-2c, [Fe2{-1:3-C(Et)=C(Et)C=N(Me)(Xyl)}(-CO)(CO)(Cp)2][SO3CF3] (3), 4, and 5a have been established by X-raydiffraction studies.
CR') insert into the metal-isocyanide bond of [Fe2(CNMe)(CO)3(Cp)2] (1), under UVirradiation, affording the complexes [Fe2{-1:3-C(R)C(R')C=N(Me)}(-CO)(CO)(Cp)2] (R = R'= Ph,2a; R = R' = Me, 2b; R = R' = Et, 2c; R = Ph, R' = H, 2d; R = Tol, R' = H, 2e; R = SiMe3, R' =H, 2f; R = Me, R' = H, 2g; R = CH2OH, R' = H, 2h; Tol = 4-MeC6H4), with displacement of one COligand. Compounds 2b,c exist as a mixture of cis and trans isomers (with reference to the mutual Cpposition), whereas 2a,d-h exclusively have the cis geometry. The insertion of terminal alkynes isregioselective, since C-C bond formation occurs selectively between the isocyanide and the nonsubstitutedcarbon of HCCR. Compound 1 reacts with 2 equiv of HCCCO2Me under UV irradiation, affording[Fe2{-2:4-C(OH)C(CO2Me)C(H)CN(Me)(CH=CHCO2Me}(CO)(Cp)2] (4). Complexes 2a,c undergoelectrophilic addition at the N atom by treatment with HSO3CF3, allyl iodide (ICH2CH=CH2), and methylchloroformate (ClCOOMe), affording the corresponding vinyliminium cations [Fe2{-1:3-C(R)=C(R)C=N(Me)(E)}(-CO)(CO)(Cp)2]+ (R = Ph, E = H, 5a; R = Et, E = H, 5b; R = Ph, E = CH2CH=CH2,6; R = Ph, E = CO2Me, 7). The reactions of 6 with NaBH4 and NBu4CN afford [Fe2{-1:3-C(Ph)C(Ph)=C(H)N(Me)(CH2CH=CH2)}(-CO)(CO)(Cp)2] (8) and [Fe2{-1:3-C(Ph)C(Ph)C(CN)N(Me)(CH2CH=CH2)}(-CO)(CO)(Cp)2] (9), respectively. The molecular structures of cis-2c, [Fe2{-1:3-C(Et)=C(Et)C=N(Me)(Xyl)}(-CO)(CO)(Cp)2][SO3CF3] (3), 4, and 5a have been established by X-raydiffraction studies.