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Recently, Nanoarchitectonics has been introducedas a new concept that refers to a technology systemfor arranging nanoscale structural units in a requiredarchitecture. Multifunctional properties are achieved by acombination of several materials in a well-defined architecture.In the frame of this concept, composite nanoarchitecturesrepresent a new class of nanostructured entitiesthat integrate various dissimilar nanoscale building blocksincluding clusters, particles, wires and films. The heterogeneouscomposite nanostructured materials are composedby definition of multi-(nano)components, each tailored toaddress different requirements. As one of the nanocomponents,nanometer sized metal clusters (

Whereas standard strong bases (n-BuLi, s-BuLi/TMEDA, n-BuLi/t-BuOK, TMPMgCl·LiCl, and LDA) reduce the N═N bond of the parent azobenzene (Y = H), aromatic H→Li permutation occurs with LTMP when a suitable director of lithiation (Y = OMe, CONEt2, F) is present in the benzene residue of the azo compound. The method allows direct access to new substituted azobenzenes.

Directed remote aromatic metalations are useful synthetic transformations allowing for rapid regioselective access to elaborate highly substituted carbocyclic aromatic and heteroaromatic systems. This review unravels the tangle of data reported on directed remote aromatic metalations. Through a careful analysis of critically selected examples, advanced rationalizations of remote metalation regioselectivities are presented. These extend beyond the complex-induced proximity effect (CIPE). Mechanisms, driving forces, and parameters influencing remote metalations are discussed. An understanding of these metalation mechanisms enables more accurate predictability of justification of regiochemical outcomes of these useful synthetic transformations.

It allows a new and effective access to a number of 1-substituted 2-naphthoic acids and 2-substituted 1-naphthoic acids.

The Meyers reaction, i.e. the nucleophilic aromatic substitution reaction between aryloxazolines with organolithium and organomagnesium reagents is a very efficient and reliable method for the formation of new carbon-carbon and carbon-heteroatom bonds. The aim of this review is to present a general overview of this reaction in chiral and racemic form, emphasizing its scope and limitations. The literature is covered since 1994.

It is demonstrated that treatment of azadienes of type (I) and (VI) with diazomethane provides aziridines as main products.

Concise general routes to mixed 2,3-dihalobenzoic acids and related acetophenones based on directed ortho -metalation and ipso-desilylation reactions are described.

Benzoic acid gives the ortho-lithiated species 1 under standard conditions (BusLi–TMEDA–THF, –90 °C). Reaction of 1 at –78 °C with either methyl iodide, dimethyl disulfide, hexachloroethane, or 1,2-dibromotetrachloroethane gives the ortho-substituted product. Intramolecular competition between the carboxylic acid and methoxy, chloro, fluoro, or diethylamido functions in ortho- and -para-substituted benzoic acids establishes the carboxylic acid group to be of intermediate capacity in directing metallation. Complimentarity of directing effects is observed with the chloro and fluoro groups in the meta-substituted benzoic acids but not with the methoxy and trifluoromethyl groups. Electrophile introduction into meta- and para-lithiated benzoates occurs with equal efficacy and comparable scope. The 2,4-dihalogenobenzoic acids undergo hydrogen/metal exchange at the position flanked by both halogen substituents. 2,2-Difluoro-1,3-benzodioxole-4-carboxylic acid undergoes lithiation adjacent to the oxygen atom. By use of such methods, routes to benzoic acids contiguously tri- and tetra-substituted with a variety of functionalities have been developed.

Intermolecular competition between equimolecular amounts of benzoic acid and substituted aromatics (PhCONEt2, PhOCONEt2, PhCONHMe, PhSO2NHMe, PhSO2NEt2, phenyloxazoline, PhNMe2, PhCH2NMe2, and PhOMe) establishes the carboxylic acid group to be of intermediate capacity in directing metalation.

1,3-Dienylborate 3 is found to be a very reactive diene for the Diels-Alder reaction to produce functionalized cyclic allylborates in good yields.

Various α-alkoxy boronic esters have been synthetized by borylation of α-alkoxyorganolithium reagents generated via tin/lithium exchange. This reaction occured with retention of configuration and gave access to α-hydroxy and α-amino boronic esters.

The monolithium acetylide method is probably the most widely used ethynylation and alkynylation reaction.1 Monolithium acetylide (1) disproportionates readily above -25 °C into the more stable dilithium carbide (2) and acetylene.2 Liquid ammonia which is utilized in processes claimed to have industrial economics1,3 serves not only as a solvent but also as a stabilizing agent. When ammonia is removed completely, disproportionation occurs. The use of the monolithium acetylideethylenediamine complex which is produced by allowing N-lithioethylenediamine to react with acetylene in various solvents permits isolation and eliminates the need for liquid ammonia.4,5 1 may also be prepared from acetylene and lithium in benzene/hexamethylphosphoric triamide.6 However, the stabilizing effect of all of these complexing agents and solvents greatly diminishes the reactivity of the acetylide toward alkylating agents.

The Horner-Wadsworth-Emmons (HWE) reaction was performed on methyl 3,6-di-O-benzoyl-2-deoxy-α-D-glycero-hex-2-enopyranosid-4-ulose (1) with the potassium enolates of dimethyl [(methoxycarbonyl)methyl]phosphonate (2) or diethyl [(ethoxycarbonyl) methyl]phosphonate (3) under different conditions (metallic cation and solvent) in order to study regio- and stereochemical aspects of the reaction. In the presence of lithium ions, no reaction took place. When sodium enolates were employed, 1,2-addition was the main reaction in chelating solvents, whereas the 1,4-adduct is favoured in the less polar, non chelating toluene. Only 1,2-addition was observed with potassium enolates. Evidence of phosphonate-phosphate rearrangements through five membered cyclic intermediates is described.

N-Alkyl/aryl-α- and β-aminoalkylphosphonic acids can be effectively prepared by reductive alkylation of azidoalkylphosphonates with organodichloroboranes. The reaction is accompanied by simultaneous dealkylation of the phosphonates occurring via polyborophosphonates.

Boron tribromide cleanly and quantitatively converts dimethyl-, diethyl-, diisopropyl-, and ditertiobutyl phosphonates RP(O)(OR’)2 into the corresponding phosphonic acids RP(O)(OH)2 via methanolysis. The use of boron tribromide is compatible with a variety of functionalities in the R group.

In this contribution, we present a review of our recent works about the design of phosphor nanoparticles and materials based on [Mo6X14]2− cluster units (X = Cl, Br, I) as well as the functionalization of monocrystalline Si(111) surfaces by Mo6 clusters. Our purpose was to use the specific properties of cluster units found in inorganic solids for the design of new nanomaterials with potential applications in nanotechnologies (e.g. phosphor dyes for bio labelling, light emitting diodes, redox active molecular junctions…) using soft chemistry techniques. Phosphor Cs2Mo6X14@SiO2 nanoparticles emitting in 550–900 nm upon photo-excitation were synthesised using a ‘water in oil’ microemulsion technique. They exhibit a regular shape (~45 nm) and are based on [Mo6X14]2− cluster units and Cs+ counter cations embedded in a silica matrix. ((n–C4H9)4N)2Mo6Br14@ZnO colloids and nanopowders are based on the association of ZnO crystalline nano-particles with Mo6 cluster units adsorbed on their surface. They exhibit a large emission window in the visible region that can be tuned by modulation of the excitation wave length in order to selectively obtain the emission of either clusters units or ZnO nanocrystals or of both entities. Functionalized surfaces were obtained by the attachment of cluster units on a Si(111) surface through pyridine end capped organic chains using a multi-step procedure. Modified surfaces were characterized by X-ray photoemission spectroscopy (XPS), atomic force microscopy (AFM), IR and electrochemical analysis. The surface coverage can be modulated by the controlled introduction of inert organic chains among pyridine end-capped ones before the cluster anchoring step.

The new sequential stereoselective synthesis of diversely substituted 9H-fluoren-9-ones by ortho-lithiation/Bu3SnCl quench of unprotected benzoic acids followed by Stille cross-coupling reaction and remote metalation is reported.

Preparation and characterization of a luminescent hybrid nanocomposite, ( (n‐C4H9)4N)2Mo6Br14@ZnO, is achieved by using a straightforward fabrication process. The hybrid nanocomposite can be applied both under organosol and solid‐state conditions. PL experiments show that the intrinsic photophysical properties of the cluster anion [Mo6Br14]2− are not affected by its inclusion in the ZnO organosol. The obtained nanocomposite can be applied as a versatile luminescent nanomaterial with emissions ranging from 430 to 850 nm.

New general methodology of value in aromatic chemistry based on ortho-metalation sites in o-, m-, and p-anisic acids (1-3) (Scheme 1) is described. The metalation can be selectively directed to either of the ortho positions by varying the base, metalation temperature, and exposure times. Metalation of o-anisic acid (1) with s-BuLi/TMEDA in THF at -78 degrees C occurs exclusively in the position adjacente to the carboxylate. On the other hand, a reversal of regioselectivity is observed with n-BuLi/t-BuOK. With LTMP at 0 degrees C, the two directors of m-anisic acid (2) function in concert to direct introduction of the metal between them while n-BuLi/t-BuOK removes preferentially the proton located ortho to the methoxy and para to the carboxylate (H-4). s-BuLi/TMEDA reacts with p-anisic acid (3) exclusively in the vicinity of the carboxylate. According to these methodologies, routes to very simple methoxybenzoic acids with a variety of functionalities that are not easily accessible by other means have been developed (Table 1).

Whereas treatment of unprotected naphthalene-1-carboxylic acid with alkyllithiums (RLi) affords 1,4-addition products, the reaction with LTMP/Me3SiCl under in situ quench conditions provides the ar...

Upon treatment of 3-chloro/bromobenzoic acids with hindered lithium dialkylamides (LDA or LTMP) at -50 degrees C, lithium 3-chloro/bromo-2-lithiobenzoates are generated. These dianions can be trapped as such to afford after electrophilic quenching a variety of simple 2-substituted-3-chloro/bromobenzoic acids. The 3-bromo-2-lithiobenzoate is less stable than the corresponding 3-chloro derivative and partly eliminates lithium bromide, thus setting free lithium 2,3- and 3,4-dehydrobenzoates that can be intercepted in situ with the hindered base.

Treatment of methyl linoleate with 4-phenyl-1,2,4-triazoline-3,5-dione affords 1:1 adducts resulting from ene addition, and 1:2 adducts formed by ene addition followed by Diels Alder cycloaddition....