dimethyl diazomalonate has been found to insert into the N-H bond of sterically hindered secondary aliphaticamines to afford hinderedtertiaryaliphaticamines in quite satisfactory yields. For example dimethyl 2-(dicyclohexylamino)propanedioate was formed in 85% yield from dicyclohexylamine, and the severely hindered dimethyl 2-(2,2,6,6-tetramethyl-1-piperidinyl)propanedioate was formed in 38% yield