Displacements at the nitrogen of lithioalkoxylamides by organometallic reagents

The conversions of N-(o-bromobenzyl)methoxylamine to N-acetylbenzoazetine (1), of N-(3-(o-bromophenyl)-n-propyl)methoxylamine to N-acetyltetrahydroquinoline (2), and of N-(4-(o-bromophenyl)-n-butyl)-methoxylamine to N-acetylbenzazapine (3) illustrate the use of this displacement reaction to form nitrogen-containing rings in an exocyclic reaction mode. An x-ray structural determination is reported for 1. The formations of anilides by amination of aromatic organolithium reagents with lithium methoxylamide is also reported. Lithium reagents are found to be more effective than Grignard, copper, or zinc reagents in these displacements, and the yields decrease as the size of the substituents around nitrogen increases. The endocyclic restriction test is used to show that this displacement on nitrogen cannot occur within the endocyclic confines of a seven-membered ring. A S{sub N}2 reaction pathway in a lithium complex is considered to be supported by these results.