The use of organometallic or –semimetallic 'ate complexes in organic synthesis has developed unequally. If borates, aluminates, zincates or cuprates already play an important role, other 'ate complexes have met a more recent (e.g. magnesiates or manganates, for example) or even nonexistent (e.g. calciates) development. With two metals and several ligands organized around the central metal, the 'ate complex has a typical and adjustable reactivity. So, depending on its nature, the 'ate complex behaves in different ways towards a substrate: the central metal of the 'ate complex can react either by electron transfer, or as a nucleophile, or even by transferring one of its ligands. Because of the expertise of the project partners in the field of bimetallic bases, the latter has particularly drawn their attention since the 'ate complex can play the role of a base by giving a ligand. The synthesis of functionalized aromatics, and in particular heterocycles, is an important challenge due to the numerous applications of such structures. Although there has been clear progress in the use of classical bases to deprotonate such substrates, many problems remain and justify the development of new tools proceeding at room temperature, tolerating the presence of functional groups, allowing different regioselectivities, and giving adjustable reactivities to the deprotonated rings. Our aim is therefore to develop activated 'ate compounds by varying the central metal and adding adequate metal ligands to promote chemo- and regioselective deprotonation of aromatics and heteroaromatics, notably those for which classical bases are not much suitable, and to study the subsequent functionalization. A better understanding of the behaviour of 'ate compounds will be obtained with the help of advanced NMR experiments (collaboration with G. Hilmersson, Sweden), XRay analyses (A. Wheatley, UK) and theoretical calculations (collaboration with M. Uchiyama, Japan). This will be particularly useful to study the behaviour of mixed 'ate complexes that will be used in asymmetric synthesis. In addition to the potential use for the access to targets of biological interest, the development of these methods will allow the synthesis of building blocks for various applications such as material science ans supramolecular chemistry.
Philippe GROS (UNIVERSITE DE NANCY I [HENRY POINCARE])
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
UNIVERSITE DE NANCY I [HENRY POINCARE]
UNIVERSITE DE RENNES I
Help of the ANR 462,000 euros
Beginning and duration of the scientific project: - 48 Months