Reaction chemistry between molybdenum complex CpMo(CO)2(.eta.3-2-vinylallyl) and electrophiles: new carbon-carbon bond formation through molybdenum .eta.4-trimethylenemethane cationic intermediates

[[abstract]]The compound CpMo(CO)2(eta3-vinylallyl) (5) underwent a novel cyclization with TCNE and PhCHO (BF3-catalyzed) in CH2Cl2 to afford a six-membered ring product. Treatment of 5 with PhCHO/BF3.Et2O in benzene yielded a Mo-eta4-trimethylenemethane salt, generated from the electrophilic addition of PhCHO to the vinyl group of 5. Characterization of this cation has been achieved by IR and H-1 NMR spectra and by its subsequent reaction with NaBH3CN and R2CuLi (R = Ph, PhC=C). Formation of this trimethylenemethane cation is also observed for a similar BF3-catalyzed reaction between methyl vinyl ketone and acetone in benzene. The synthetic utility of this carbon-carbon-forming reaction in organic synthesis has been investigated and is described.[[fileno]]2010327010066[[department]]化學