1,3,5-trisubstituted 1,4-diazepin-2-ones

Six 1,3,5-trisubstituted 1,4-diazepin-2-ones were synthesized by a sequence featuring the cascade addition of vinyl Grignard to N-[Boc-aminoacyl]-N-alkyl-beta-amino esters, followed by Boc group removal and annulation by a reductive amination. Relative to the parent sequence employing N-Boc-aminoacyl beta-amino esters to make 3,5-disubstituted heterocycle, the additional N-alkyl substituent caused a noticeable acceleration and gave relatively higher yield in the 1,4-diazepin-2-one annulation.