Abstract
CpW(CO) 2 [η 3 -2-(phenylethynyl)allyl] (2) was prepared from the reaction between CpW-(CO) 3 Na and 2-methylene-4-phenyl-3-butyn-1-yl tosylate, followed by decarbonylation with Me 3 NO. Treatment of 2 with CF 3 SO 3 H in cold CDCl 3 produced a mixture of [CpW(CO) 2 -(η 4 -1-(benzylidene)trimethylenemethane)]X (3a) and CpW(CO) 2 (η 3 -2-CH 2 X-4-phenyl-2,3-butadien-1-yl) (3b) (X = CF 3 SO 3 ), which were characterized with 1 H and 13 C NMR spectra. Treatment of this mixture (3a,b) with a variety of nucleophiles gave compounds of the type CpW(CO) 2 (η 3 -2-CH 2 X-4-phenyl-2,3-butadien-1-yl) (X = OH (4a), OMe (4b), iBuNH (4c), Me (4d), Ph (4e), CCPh (4f), H (4g)). In the presence of Bu 4 NI, protonation of 4d-e with CF 3 -SO 3 H in cold CH 2 Cl 2 produced CpW(CO)I[η 4 -(2-PhCH 2 -3-XCH 2 )vinylketene] (X = Me (6a), Ph (6b)), the structural identity of which was established from an X-ray diffraction study of the analogous complex CpW(CO)I[η 4 -(2-PhCH 2 -3-ICH 2 )vinylketene] (6c). Treatment of 2 with a mixture of acetaldehyde and BF 3 ·Et 2 O in cold CH 2 Cl 2 , followed by reduction of NaBH 3 -CN gave CpW(CO) 2 (η 3 -2-methyl-4-phenyl-5-methyl-2,4-pentadien-1-yl) (7), which was characterized by X-ray structural analysis.