| Aminations of formal carbanions by alkoxylamines and sulfonylhydroxylamines have been studied. The synthetic utility of the reaction with alkoxylamines has been studied, and the mechanisms of amination by alkoxylamines and arylsulfonylhydroxylamines have been investigated.; We have investigated a number of variants of the methoxylamine amination methodology. Aryllithium reagents are aminated in generally good yield, and cuprate reagents are aminated in slightly lower yields than the corresponding organolithium reagents. Zinc and Grignard reagents give low yields of aminated product. We have found that this amination methodology is sensitive to substitution on the nitrogen of the aminating reagent. We have synthesized a tertiary amine in fair yield by the reaction of a tertiary alkoxylamine with sec-butyllithium. Alkoxylamines are apparently the only aminating reagents that can give primary, secondary or tertiary amines, depending on the substitution on nitrogen.; We have synthesized various nitrogen heterocycles using this methodology. The first synthesis of N-acetyl benzoazetine was accomplished by this approach. The synthesis of intermediate sized heterocycles is difficult, as can be seen in the decreasing yield when comparing the six membered system to the eight membered system. It appears that methoxylamine is the only reagent that benefits from formation of the lithium salt, as attempts to activate other known aminating reagents with methyllithium were unproductive. By using the endocyclic restriction test in a seven membered ring, we have obtained more evidence favoring an S{dollar}sb{lcub}rm N{rcub}{dollar}2-like mechanism for this transformation. We have attempted to use the endocyclic restriction test and the double labeling technique to ascertain if there is a geometrical requirement for the transfer of the nitrogen from a N,N-disubstituted-arylsulfonylhydroxylamine to an organometallic reagent. Despite a number of successful test reactions, we were unable to develop a system where we could employ this mechanistic methodology. However, we were able to determine that these reactions probably proceed by an S{dollar}sb{lcub}rm N{rcub}{dollar}2-like process by showing that the nitrogen of the aminating reagent can be transferred intermolecularly. |
