BASE-PROMOTED HYDROALKYLATION REACTIONS OF THE ETA(5)-C(5)ME(5) LIGAND COORDINATED TO RHODIUM - PROBING A MECHANISM - NEW COMPOUNDS WITH THE ETA(5)-C(5)ME(4)CF(3) LIGAND

Dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer, [{(eta(5)-C(5 )Me(5))RhCl2}(2)] (1), reacts with diphenylvinylphosphine to produce [ (eta(5)-C(5)Me(5))Rh{CH2CHP(C6H5)(2)}Cl-2] (2) and [(eta(5)-C(5)Me(5)) Rh{CH2CHP(C6H5)(2)}Cl-2]X (3, X = Cl- (a), PF6- (b)). In acetonitrile, compound 1 undergoes a base-promoted hydroalkylation reaction with po tassium tert-butoxide and diphenylvinylphosphine to produce a(5)-C(5)M e(3)-1,3-[CH2CH2CH2P(C6H5)(2)](2)}RhCl]X (4, X = Cl- (a), PF6- (b), BP h(4)(-) (c)) and a(5)-C(5)Me(3)-1,2-[CH2CH2CH2P(C6H5)(2)](2)}RhCl]X (5 , X = Cl- (a), PF6- (b), BPh(4)(-) (c)). Compounds 4a-c and 5a-c conta in chelating 1,3- and 1,2- iphenylphosphino)propyl)trimethylcyclopenta dienide ligands. Compounds 2 and 3 are precursors on the pathway towar d formation of 4a and 5a. Compound 1 reacts with allyldiphenylphosphin e to produce [(eta(5)-C(5)Me(5))Rh{CH2CHCH2P(C6H5)(2)}Cl-2] (6) and [( eta(5)-C(5)Me(5))Rh{CH2CHCH2P(C6H5)(2)}Cl-2]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 o f products that may contain hydroalkylation adducts. rifluoromethyl)te tramethylcyclopentadienyl}rhodium (III) dimer, [{(eta(5)-C(6)Me(4)CF(3 ))RhCl2}(2)] (8), reacts with diphenylvinylphosphine to produce [(eta( 5)-C(6)Me(4)CF(3))Rh{CH2CHP(C6H5)(2)}Cl-2] (9), however the bis(phosph ine) analog cannot be isolated or characterized. In refluxing ethanol, compound 8 reacts with diphenylvinylphosphine in the absence of potas sium tert-butoxide to undergo hydroalkylation accompanied by conversio n of the CF3 group into a carboethoxy functionality producing )-C-5(CO (2)Et)Me(3)-2-[CH2CH2CH2P(C6H5)(2)]}RhCl2] (10). Complexes 3b, 7b, and 10 were characterized by single-crystal X-ray crystallography.