Double Allylation Reactions of (2-Azaallyl)stannanes:  Synthesis of N,N-Bis(3-butenyl)amines and Their Conversion to 2,3,6,7-Tetrahydroazepines via Ring-Closing Metathesis

Treatment of (2-azaallyl)stannanes (i) with 2.2 equiv of allylmagnesium bromide afforded good yields of N,N-bis(3-butenyl)amines derivatives (ii), which were subjected to ring-closing metathesis to afford 2,3,6,7-tetrahydroazepines (iii). Thus, (2-azaallyl)stannanes are the synthetic equivalents of amine α,α‘-dications.