Hyperconjugation with lone pair of morpholine nitrogen stabilizes transition state for phenyl hydroxylation in CYP3A4 metabolism of (S)-N-[1-(3-morpholin-4-yl phenyl) ethyl]-3-phenylacrylamide

Using quantum chemical modelling we describe a novel effect in the mechanism of CYP3A4 metabolism for the arene substrate with o-substituent yielding a lone pair donation to conjugate π system; this will compensate for the loss of aromaticity on formation of the tetrahedral complex and lower the rate-determining energy barrier.