Reactions of N,N ',N ''-trimethyl-1,4,7-triazacyclononane with butyllithium reagents

Treatment of N, N', N-trimethyl-1,4,7-triazacyclononane (Me(3)tacn) with a range of alkyllithiums led to metallation of the N-methyl groups and, in the case of (BuLi)-Bu-t, to the formation of an unusual mu-Bu-t complex; the latter undergoes clean transmetallation with toluene to form a Me(3)tacn complex of benzyllithium.