Mulvey, Robert and Armstrong, David R. and Conway, Ben and Crosbie, Elaine and Kennedy, Alan and Robertson, Stuart (2011) Structurally powered synergic 2,2,6,6-tetramethylpiperidine bimetallics: new reflections through lithium-mediated ortho aluminations. Inorganic Chemistry, 50 (24). pp. 12241-12251. ISSN 0020-1669Full text not available in this repository. (Request a copy from the Strathclyde author)
Recent times have witnessed many notable advances in metalation chemistry with halide salt supported strategies and alkali-metal mediated metalation being particularly prominent. This article begins with a brief account of both of these avant garde metalation methods focusing on selected recent examples not covered previously in a review. New results in the area of Alkali-Metal Mediated Alumination (AMMAl) are also presented. Thus, the putative lithium aluminate base THE center dot Li(mu-TMP)(2)Al(Bu-i)(2) (4) is shown to act via TMP basicity to efficiently ortho deprotonate a variety of functionalized aromatic molecules at room temperature, tolerating carboxamide and halide functionalities. These metalated species are electrophilically quenched with elemental iodine. Crystal structure determinations of the metalated intermediates confirm unequivocally that direct alumination of the substrates has occurred. Since the homometallic lithium or aluminum reagents are unable to effect such deprotonations these reactions are synergic in nature and can be considered examples of AMMAl. Drawing together previously published work in the field of AMMAl, together with other pertinent experimental Observations and new density functional theory (DFT) computational studies, we propose a potential rationale for the "unusual" reactivity patterns witnessed in this branch of heterometallic synthetic chemistry with respect to other Alkali Metal Mediated Metalations which appear to behave in a more conventional manner.
|Keywords:||directed ortho-metalation, chemoselective functionalization, aluminium compounds, INVERSE CROWN CHEMISTRY, DEPROTONATIVE METALATION, crystal structures, zincation, Chemistry, Physical and Theoretical Chemistry, Inorganic Chemistry|
|Subjects:||Science > Chemistry|
|Department:||Faculty of Science > Pure and Applied Chemistry|
|Depositing user:||Pure Administrator|
|Date Deposited:||16 Jan 2012 15:39|
|Last modified:||27 Apr 2016 18:06|