Addition of alkynes at bridging vinyliminium ligands in diiron complexes: Unprecedented diene formation by enyne-like metathesis

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• 作者：Luigi  ; Busetto^a ; Fabio  ; Marchetti^b ;   ; ¹ ;   ; ^{fabmar@dcci.unipi.it} ; Stefano  ; Zacchini^a ; Valerio  ; Zanotti^a ;   ; ^{valerio.zanotti@unibo.it}
• 关键词：Vinyliminium ; Diiron complexes ; C&ndash ; C bond formation ; Alkyne insertion ; Enyne metathesis ; Cycloaddition
• 刊名：Journal of Organometallic Chemistry
• 出版年：2011
• 出版时间：15 December 2011
• 年：2011
• 卷：696
• 期：25
• 页码：4051-4056
• 全文大小：435 K

文摘

The zwitterionic bridging vinyliminium complex [Fe₂{¦Ì-¦Ç¹:¦Ç³-C(Tol)C(CS₂)CN(Me)₂}(¦Ì-CO)(CO)(Cp)₂] (5a) undergoes the addition of two equivalents of MeO₂C¨CCC¨CCO₂Me affording the bridging bis-alkylidene complex [Fe₂{¦Ì-¦Ç¹:¦Ç³-C(Me)C{C(CO₂Me)C(CO₂Me)CSC(CO₂Me)C(CO₂Me)S}CNMe₂}(¦Ì-CO)(CO)(Cp)₂] (6). One alkyne unit inserts into a C¨CCS₂ bond of the bridging ligand, with consequent rearrangement that leads to the formation of a diene. The reaction shows analogies with the enyne metathesis. The second alkyne is incorporated into the bridging frame via cycloaddition at the thiocarboxylate function, affording a 1,3-dithiolene. The complexes [Fe₂{¦Ì-¦Ç¹:¦Ç³-C(R?C(CS₂)CN(Me)(R)}(¦Ì-CO)(CO)(Cp)₂] (R?=?Xyl, R¡ä??Tol, 5b; R?=?p-C₆H₄OMe, R¡ä??Me, 5c; Xyl?=?2,6-Me₂C₆H₃), treated with MeO₂C¨CCC¨CCO₂Me and then with HBF₄, undergo the cycloaddition of the alkyne with the dithiocarboxylate group and protonation of the dithiocarboxylate carbon, affording the complexes [Fe₂{¦Ì-¦Ç¹:¦Ç³-C(R?C{C(H)SC(CO₂Me)C(CO₂Me)S}CN(Me)(R)}(¦Ì-CO)(CO)(Cp)₂][BF₄] (R?=?Xyl, R¡ä??Tol, 7a; R?=?p-C₆H₄OMe, R¡ä??Me, 7b), respectively.

The X-ray molecular structure of 6 has been determined.