Nitrilimines: Evidence for the Allenic Structure in Solution, Experimental and <i>Ab Initio</i> Studies of the Barrier to Racemization, and First Diastereoselective [3 + 2]-Cycloaddition
solution NMR studies of nitrilimines 4 and 7 demonstrate that they possess a bent allenicstructure. The free energy of activation for racemization is ca. 30 kJ mol(-1). Ab initio/DFT studies performed on nitrilimine with C-P(S)H-2 and N-PH2 substituents 10 show that the most likely pathway for the racemization process is inversion at the carbon atom, followed by rotation of the PSR(2) fragment. Bis(trityl)nitrilimine