181485-21-2Relevant academic research and scientific papers
Base-promoted hydroalkylation reactions of the η5-C5Me5 ligand coordinated to rhodium: Probing a mechanism. New compounds with the η5-C5Me4CF3 ligand
Barthel-Rosa, Luis P.,Catalano, Vincent J.,Maitra, Kalyani,Nelson, John H.
, p. 3924 - 3934 (2008/10/08)
Dichloro(pentamethylcyclopentadienyl)rhodiumd(III) dimer, [{(η5-C5Me5)RhCl2}2] (1), reacts with diphenylvinylphosphine to produce [(η5-C5Me5)Rh{CH2CHP(C 6H5)2}Cl2] (2) and [(η5-C5Me5)Rh{CH2CHP(C 6H5)2}2Cl]X (3, X = Cl- (a), PF6-(b)). In acetonitrile, compound 1 undergoes a base-promoted hydroalkylation reaction with potassium tert-butoxide and diphenylvinylphosphine to produce [{η5-C5Me3-1,3-[CH2CH 2CH2P(C6H5)2]2}RhCl]X (4, X = Cl- (a), PF6- (b), BPh4- (c)) and f{η5-C5Me3-1,2-[CH2CH 2CH2P(C6H5)2] 2}RhC]X (5, X = Cl- (a), PF6- (b), BPh4- (c)). Compounds 4a-c and 5a-c contain chelating 1,3- and 1,2- bis-((diphenylphosphino)propyl)trimethylcyclopentadienide ligands. Compounds 2 and 3 are precursors on the pathway toward formation of 4a and 5a. Compound 1 reacts with allyldiphenylphosphine to produce [(η5-C5,Me5)Rh{CH2CHCH 2P(C6H5)2}Cl2] (6) and [(η5-C5-Me5)Rh{CH2CHCH 2P(C6H5)2}2Cl]X (7, X = Cl- (a), PF6- (b)). In acetonitrile, compound 1 reacts with allyldiphenylphosphine in the presence of potassium tert-butoxide to produce a complex mixture of products that may contain hydroalkylation adducts. Dichloro{(trifluoromethyl)tetramethylcyclopentadienyl}rhodium(III) dimer, [{(η5-C5Me4CF3)RhCl 2}2}2] (8), reacts with diphenylvinylphosphine to produce [(η5-C5Me4CF3)Rh{CH 2CHP(C6H5)2}Cl2] (9), however the bis(phosphine) analog cannot be isolated or characterized. In refluxing ethanol, compound 8 reacts with diphenylvinylphosphine in the absence of potassium tertbutoxide to undergo hydroalkylation accompanied by conversion of the CF3 group into a carboethoxy functionality producing [{η5-C5(CO2Et)Me3-2-[CH 2CH2CH2P(C6H5) 2]}RhCl2] (10). Complexes 3b, 7b, and 10 were characterized by single-crystal X-ray crystallography.
