theoretical studies on chiral formamide-mediated asymmetric allylation of aldimines

The enantioselective allylation of simple aldimines has been studied making use of density functional theory calculations. the proposed reaction mechanism includes eight possible transition-state structures, four of them leading to the r and four to the s enantiomer, respectively. despite the fact that this multiple transition-state problem depends on subtle effects, all density functionals and basis sets employed indicate that the r isomer is favourably formed in contradiction to earlier published experimental results. the discussion of the transition-state structures and the comparison with literature results give insight into the origin of the observed stereoselectivity.