A hexahydro-s-indacene based NHC ligand for olefin metathesis catalysts

作者：Savka Roman D; Plenio Herbert^*

来源：Journal of Organometallic Chemistry, 2012, 710: 68-74.

DOI：10.1016/j.jorganchem.2012.03.015

• N-Heterocyclic carbene
• Ruthenium
• Olefin metathesis
• Ring closing metathesis

The reaction of amino hexahydro-s-indacene with glyoxal, reduction of the diimine to the diamine and cyclization with HC(OEt)(3) yields the new 1,3-bis(1,2,3,5,6,7-hexahydro-s-indacen-4-yl)-4,5-dihydro-1H-imidazol-3-ium chloride 3 center dot HCl with conformationally restricted alkyl groups ortho to the heterocyclic substituent. Reaction of 3 center dot HCl with Ag2O gave the respective silver NHC complex (yield 78%), which was used to synthesize the respective (3) IrCl(cod) (yield 86%), whose reaction with CO gave (3) IrCl(CO)(2) 6 (yield 98%). The Grubbs II type complex [(3) RuCl2(PCy3)(3-phenyl-indenylid-1-ene)] was synthesized (yield 68%) and converted into [(3) RuCl2(py)(3-phenyl-indenylid-1-ene)] (yield 78%) in pyridine solvent. With this complex the respective Grubbs-Hoveyda species (yield 68%) and two bisNHC complexes [(3)(NHCewg) RuCl2(3-phenyl-indenylid-1-ene)] (yield 87%, 89%) were obtained. The stereoelectronic properties of the new NHC ligand were determined employing IR spectroscopy, cyclic voltammetry and buried-volume analysis based on the crystal structure of complex 6. The activity of the ruthenium complexes in RCM reactions of sterically hindered substrates was tested.

• 出版日期2012-7-1