346620-45-9Relevant academic research and scientific papers
Synthesis and coordination chemistry of chelate ligands containing cyclopentadienyl, indenyl and fluorenyl donors - Diastereoselectivity and NMR structure analysis
Vogelgesang, Joachim,Frick, Axel,Huttner, Gottfried,Kircher, Peter
, p. 949 - 971 (2007/10/03)
The functionalised oxetane O(CH2)2C(CH2Br)(CH2OMs) (1) is transformed into tripod ligands ROCH2C(CH2PPh2)(CH2PR′ 2)(CH2Cp#) (R = H, SiMe3; R′ = Ph, Et; Cp# = indenyl, fluorenyl) (4) in a few steps. Epichlorohydrin O(CH2)CH(CH2Cl) (5) allows for diastereoselective one-pot syntheses of the Cp-functionalised chelate ligands (Cp#CH2)C(H)OH(CH2PPh2) (Cp# = Cp, indenyl, fluorenyl) (6). The SiMe3-protected derivatives of these ligands react with RuCl2(PPh3)3 to produce {Me3SiOCH(CH2-η1PPh2)(CH 2-η5-Cp#)Ru(PPh3)(Cl)} (Cp# = Cp, indenyl) (15) with high diastereoselective preference. With the same starting material, tripod ligands 4 form Me3SiOCH2C(CH2-η1PPh 2)(CH2-η1PR2)(CH2 -η5-Indenyl)RuCl (R = Ph, Et) (16). As shown by complete NMR spectroscopy based structure analyses (DG methods) of 16, the formation of 16 (R = Et) is diastereoselective. The only diastereomer which is observed is the one in which the PEt2 donor and the phenylene part of the indenyl ligand are juxtaposed. In addition to quantitative NMR spectroscopy structure analyses, traditional analytical techniques, including X-ray analyses, were used to confirm the results.
