A series of chloro- and bromopyridines have been deprotometalated by using a range of 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal combinations. Whereas lithium-zinc and lithium-cadmium bases afforded different mono- and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium-copper combination, as demonstrated by subsequent trapping with benzoyl chlorides. The obtained selectivities have been discussed in light of the CH acidities of the substrates, determined both in the gas phase and as a solution in THF by using the DFT B3LYP method.

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The name of the game: X‐ray crystallographic analysis of Gilman‐ and Lipshutz‐type amidocuprates indicates that the presence of LiX (X=CN, I) and THF shifts the equilibrium between the two toward the Lipshutz‐type cuprate and that this is important in generating the active species for directed ortho cupration. DFT calculations show that monomeric Gilman‐type cuprates have an unprecedentedly high reactivity (see scheme, DG=directing group).

Recent advances in the selective deprotometallation of aromatic reagents using alkali metal cuprates are reported. The ability of these synergic bases to effect deprotonation under the influence of a directing group is explored in the context of achieving new and more efficient organic transformations whilst encouraging greater ancillary group tolerance by the base. Developments in our understanding of the structural chemistry of alkali metal cuprates are reported, with both Gilman cuprates of the type R2CuLi and Lipshutz and related cuprates of the type R2Cu(X)Li2 (X = inorganic anion) elucidated and rationalised in terms of ligand sterics. The generation of new types of cuprate motif are introduced through the development of adducts between different classes of cuprate. The use of DFT methods to interrogate the mechanistic pathways towards deprotonative metallation is described. Theoretical modelling of in situ rearrangements undergone by the cuprate base are discussed, with a view to understanding the relationship between R2CuLi and R2Cu(X)Li2, their interconversion and the implications of this for cuprate reactivity. The advent of a new class of adduct between different cuprate types is developed and interpreted in terms of the options for expelling LiX from R2Cu(X)Li2. Applications in the field of medicinal chemistry and (hetero)arene derivatization are explored.

TMPLi (TMP=2,2,6,6-tetramethylpiperidide) reacts with CuI salts in the presence of Et2O to give the dimers [{(TMP)2Cu(X)Li2(OEt2)}2] (X=CN, halide). In contrast, the use of DMPLi (DMP=cis-2,6-dimethylpiperidide) gives an unprecedented structural motif; [{(DMP)2CuLi(OEt2)}2LiX] (X=halide). This formulation suggests a hitherto unexplored route to the in situ formation of Gilman-type bases that are of proven reactivity in directed ortho cupration.

Efficient two-step access to azafluorenones and related compounds. Tetrahedron Letters, Elsevier, 2013, 54 (24) Abstract:Crystals of a lithiocuprate prepared from copper(I) chloride and lithium 2,2,6,6-tetramethylpiperidide (2 equiv) were isolated and analysed by X-ray diffraction as (TMP)2Cu(Cl)Li2·THF. The observation of this species is consistent with its having a role in deprotocupration-aroylation for a higher-order bis(amido)cuprate. Phenyl pyridyl ketones, phenyl quinolyl ketones and phenyl thienyl ketones were prepared in tetrahydrofuran by this sequence using the lithiocuprate and aroyl chorides as electrophiles. Diaryl ketones bearing a chloro group at the 2 position (of a pyridyl or phenyl group) thus synthesized were next converted through palladium-catalysed ring closure to polycycles of the 5H-indeno

Reactions of the [1,2-(NH)(2)C(6)H(4)](2-) dianion (LH(2)(2-)) with Cp(2)M(II) (M = V, Mn) lead to complete or partial oxidation of the metals (M), giving the V(III) compound [(η(5)-Cp)(LH(2))(2)VV(LH(2))](-)[Li(THF)(4)](+) (1) and Mn(II)(4)Mn(III)(2) oxo cage [Mn(6)(LH(2))(6)(μ(6)-O)(THF)(4)] (2).

Gilman‐ und Lipshutz‐Amidocuprate wurden einer röntgenkristallographischen Analyse unterzogen, die darauf hindeutet, dass die Gegenwart von LiX (X=CN, I) und THF das Gleichgewicht zugunsten der Lipshutz‐Cuprate verschiebt und wichtig für die Erzeugung der aktiven Spezies in dirigierten ortho‐Cuprierungen ist. Dichtefunktionalrechnungen bescheinigen monomeren Gilman‐Cupraten eine beispiellos hohe Reaktivität (siehe Schema, DG=dirigierende Gruppe).