200864-34-2Relevant academic research and scientific papers
Selective reactions of functionalized ruthenium(II) σ-alkynyl complexes with dicobalt octacarbonyl and tetracobalt dodecacarbonyl: Synthesis of cyclopentenone derivatives via intermolecular pauson-khand reactions
Cadierno, Victorio,Gamasa, M. Pilar,Gimeno, Jose?,Moreto?, Josep M.,Ricart, Susagna,Roig, Anna,Molins, Elies
, p. 697 - 706 (2008/10/08)
Treatment of [Ru{C=CCPh2(C=CH)}(η5-C9H 7)(PPh3)2] (1) with [Co2(CO)8] leads to the formation of the adduct [Ru{C=CCPh2(μ2-η2-C=CH)Co 2(CO)6}(η5-C9H 7)(PPh3)2] (3) through the selective coordination of the Co2(CO)6 fragment at the terminal alkyne group on 1. Similarly, the enynyl complex [Ru{C=CCH=CH(C=CPh)}(η5-C9H7)(PPh 3)2] ((E,Z)-2), prepared via a Wittig reaction from [Ru{C=CCH2(PPh3)}(η5-C9H 7)(PPh3)2][PF6] (5) and phenylpropargyl aldehyde, also reacts with [Co2(CO)8] to yield selectively the adduct [Ru-{C=CCH=CH(μ2-η2-C=CPh)Co2(CO) 6}(η5-C9H7)(PPh 3)2] ((E,Z)-6). Protonation of complexes 3 and (E,Z)-6 with HBF4·Et2O affords the cationic vinylidene derivatives [Ru{=C=C(H)-CPh2(μ2-η2-C=CH)Co 2(CO)6}(η5-C9H 7)(PPh3)2][BF4] (4) and [Ru{=C=C(H)CH=CH(μ2-η2-C=CPh)Co 2(CO)6}(η5-C9H 7)(PPh3)2][BF4] ((E,Z)-7), respectively. Dicobalt adduct complexes 3 and (E,Z)-6 undergo Pauson-Khand cyclization processes with strained cyclic alkenes (norbornadiene and norbornene) to afford regioselectively the tricyclic cyclopentenone derivatives 8a,b, 9a,b, (E,Z)-10, and 11. (E,Z)-6 reacts with [Co4(CO)12] to give an unprecedented ruthenium(II) vinylidene complex containing a tetranuclear butterfly type cobalt cluster (12), which has been characterized by X-ray diffraction.
