Theoretical Studies On The Hydroacylation Catalyzed By The Cobalt Catalyst

DFT calculations have been carried out to examine the mechanism of intermolecular cobalt-catalyzed hydrocylation of benzaldehyde with isoprene.All of the transition states and intermediates were performed with the B3 LYP method.Vibration analysis and intrinsic reaction coordinates(IRC)were calculated for the transition states to confirm that such structures indeed connect two relevant minima.The calculation results did not support the conventional oxidative addition mechanism.Instead,the calculations supported the oxidative cyclization mechanism which involves oxidative cyclization of benzaldehyde with isoprene,?-H elimination,Finally reductive elimination to give the unsaturated ketones.Besides,the NBO analysis and distortion/interaction reactivity analysis was performed to explain why the oxidative cyclization mechanism is more favorable.After obtaining the most favourable mechanism(the oxidative cyclization mechanism)for the Co-catalyzed hydrocalation,we next attempt to research the factors that affect the regioselectivity.We calculate other two substrates CH2=CH-CH(CN)=CH2,CH2=CH-CH(OMe)=CH2.The energy profiles calculated for the oxidative coupling reactions of benzaldehyde with diene prove that the coupling reactions of benzaldehyde with three different dienes display the same C1-regioselectivity,in spite of the fact they are very different because of their electronic properties.Then,we calculated that aldehyde substituent does not have effect on C1-regioselectivites.