The efficiency of a cyclodehydration reaction leading to benzodiazepinones is markedly improved by N-methylation of the amide link connecting the nucleophile and the electrophile, which is attributed to its favouring both the more reactive E-rotamer and the exit of the leaving group.
![(S)-2-[N-(N'-Boc-prolyl)amino]benzophenone Structure](https://image.chemsrc.com/caspic/497/1093987-00-8.png)
