The Formation of a Mixed Organolithium Aggregate Li_4R_2Bu_2 during the Heteroatom-Assisted Lithiation of 1,3-Bis(dimethylaminomethyi)-2,4,6-trimethylbenzene(R = 2,6-(CH_2NMc_2)_2-3,5-Me)_2C_6HCH_2)

摘要

In the course of our studies into the orpanometallic chemistry of the potentially tridentatc monoanionic 2,6-bis(dimethyl-aminomethyl)phenyl Hgand, compounds having special properties and reactivities were obtained: 1) metals stabilized in unusual oxidation states. 2) stabilized reactive intermediates, and 3) species showing catalytic activity. Such organcmecallic compounds have related structures in which two five-membered M-C-C-C-N chelate rings share a common M-C bond. in order to fine-tune the metal environment, we decided to investigate the properties of compounds in which the two five-membered chelate rings are extended to six-membered ones having an M-C-C unit in common. Heteroatom-assisted lithia-tion is. especially when the heteroatom belongs to a tertiary amino grouo, a valuable reaction for the synthesis of hetero-atoin-containing orgai-olithium compounds, and usually provides products of high purity with excellent yield. We therefore started our investigations with the attempted metalation of l,3-bis(dimethylaminomethyl)-2,4,6-trimethylbenzene(1)at the 2-methyl group.