Synthesis of N,N-Bis(3-butenyl)amines from 2-Azaallyl Dication Synthetic Equivalents and Conversion to 2,3,6,7-Tetrahydroazepines by Ring-Closing Metathesis

摘要

N,N-Bis(3-butenyl)amines can be prepared by the double allylation of either (2-azaallyl)stannanes or (2-azaallyl)nitriles,both of which thereby act as synthetic equivalents to amine alpha,alpha'-dications (2-azaallyl dications).Allylmagnesium bromide is the reagent of choice for the double allylation of both substrates,although allyllithium also effects the double allylation of (2-azaallyl)nitriles.Ring-closing metathesis can be performed on the N-protected amines,or with in situ protonation,on the free amines to provide 2,3,6,7-tetrahydroazepines.(2-Azaallyl)nitriles can also be monoallylated to provide N-(3-butenyl)-aminonitriles,whereas the double allylation of (2-azaallyl)stannanes cannot be stopped at monoallylation.(2-Azaallyl)silanes undergo monoallylation to give N-(3-butenyl)aminosilanes but do not undergo double allylation.