A catalytic (in Brønsted superacid) and a stoichiometric process were developed to synthesise aryl boronic esters with boron cations via electrophilic arene borylation. The treatment of CatBX (Cat = catecholate; X = Cl, Br) with the triethyl salt [Et3Si][closo-CB11H6Br6] in arene solvent gave a transient boron electrophile that reacted as a synthetic equivalent of [CatB]+ in intermolecular electrophilic aromatic borylation at 25 °C. The by-product of the reaction was a strong Brønsted acid that was able to catalyse arene borylation using CatBH at high temperature. This catalytic process furnished aryl boronic esters in high yield with H2 as the only by-product. The use of the robust and weakly coordinating anion [closo-CB11H6Br6]- and the electrophile-resistant catecholborane were crucial for the catalytic process. The reaction mixture of R2BCl (R2 = Cat, Cl4Cat, Cl2), aprotic amine and AlCl3 mainly gave a borenium salt [R2B(amine)][AlCl4] which was in equilibrium with neutral species as revealed by NMR spectroscopy and reactivity studies. This reaction mixture was effective for the regioselective borylation, by electrophilic aromatic substitution, of a range of N-heterocycles, thiophenes and anilines at room temperature. The transterification in situ provided the synthetically useful and more stable pinacol boronate esters in excellent isolated yield. This process displayed remarkable functional-group tolerance for a boron based strong Lewis acid with weak bases (for example -NMe2), ether, and halogen groups all compatible. This process represents a new and inexpensive one-pot direct arene borylation methodology for producing pinacol boronate esters.

As key components of flexible organic electronics, the synthesis of polythiophenes via less toxic and more cost-effective routes is demanded. An efficient synthetic route for the production of thienyl-containing homopolymers and copolymers has been developed. The synthetic approach consists of: i) the synthesis in high yield and high purity of thienyl borane monomers protected with N-methyliminodiacetic acid (MIDA) via C-H electrophilic borylation. This reaction uses a combination of inexpensive reagents BCl3, AlCl3, and 2,6-dichloropyridine (Cl2Py) for the regioselective electrophilic aromatic substitution of thiophenes, followed by addition of a second aprotic amine pre-esterification to reduce the Brønsted acidity of the reaction mixture. In situ esterification provided the desired thienyl MIDA boronateester monomers in one-pot at room temperature. ii) Subsequent Suzuki-Miyaura polymerisation of the synthesised monomers to produce well defined thienyl containing pie-conjugated polymers in high molecular weight and high yields. Key reaction parameters for successful Suzuki-Miyaura polymerisation of thienyl-derived MIDA boronate esters under mild temperatures (i.e., 55 °C in THF) were found: a) an optimal monomer:H2O:base ratio, which enables controlled hydrolysis of the BMIDA moiety into its corresponding boronic acid at appropriate rates for high fidelity polymerisation. b) Nature of the base, where K3PO4 provided the best results for production of homopolymers (e.g., rr-P3HT), or KOH which gave excellent results for the formation of copolymers across a range of electronically different comonomers (e.g., pCPDT-BT). Thus, it is demonstrated that the approach is a general strategy for the highly efficient production of thienyl containing pie-conjugated regioregular, regiosymmetric and Donor-Acceptor polymers.

The synthesis, photophysical and electronic properties of a series of novel boron containing fused and ladder type donor-acceptor (D-A) oligomers and polymers are reported. The synthesis was achieved through coordination of the basic functionality of the ubiquitous benzothiadiazole acceptor unit onto a boron Lewis acid followed by an electrophilic aromatic borylation resulting in the formation of fused and ladder type structures (termed borylative fusion). The novel C,N-chelated borane structures disclosed herein are a new member of a large family of tetra-coordinate organoboron compounds that are used for the construction of highly emissive materials. Upon borylation large bathochromic shifts in the absorption and fluorescence spectra were observed, DFT and cyclic voltammetry demonstrate that this is a result of a significant reduction of the LUMO energy levels whist the HOMO energy levels remains relatively unperturbed. These large bathochromic shifts lead to materials that show far red/NIR emission in the solid state with absolute quantum yields of up to 44%. Furthermore, the frontier molecular orbital energy levels of these fused structures can be modulated through judicious selection of the exocyclic boron substituents. These novel borocycles also proved stable to a range of cross-coupling conditions which facilitated further modulation of the frontier molecular orbitals and emissive properties. Borylative fusion was also applicable to D-A conjugated polymers, this represents a facile post-polymerisation functionalisation that is an effective method of modulating the photophysical properties of D-A conjugated polymers. Solution processed OLEDs with far red/NIR electroluminescence (EL) were fabricated from these materials. These devices showed good external quantum efficiency values (EQE) for the far red/NIR region of the electromagnetic spectrum (EQE > 0.4 % for maximum EL > 700 nm).

La fluidique est un outil offrant des avantages industriels notamment en termes de sécurité grâce à un meilleur contrôle thermique mais aussi une diminution des risques due à un engagement de volumes faibles. Cette technologie permet des réactions chimiques plus efficaces grâce à un système plus homogène qui impacte les rendements, la sélectivité ou encore la quantité de réactifs nécessaire. Aujourd’hui, la production de principes actifs pharmaceutiques est réalisée majoritairement en procédé batch. Ainsi, dans une première partie, la microfluidique a été appliquée à la synthèse d’un principe actif pharmaceutique. Les diverses étapes réactionnelles ainsi que les paramètres physiques du système ont été optimisés avec l’utilisation de micromélangeurs. Un procédé multi-étapes a été développé avec une productivité atteignant 100 g.h-1. Des productions ont été réalisées validant les tests préliminaires ainsi que la possibilité de production du principe actif pharmaceutique en continu.Les dérivés du bore sont quant à eux des intermédiaires réactionnels couramment utilisés pour leurs réactivités en synthèse organique. Ainsi, dans une seconde partie, la réaction de borylation électrophile a été étudiée, et plus spécifiquement la synthèse des oxa et des azaborinines grâce au complexe diisopropylamine borane (DIPAB) utilisé comme agent de borylation. Ces dernières molécules ont ensuite été fonctionnalisées grâce à des réactions d’oxydation, d’amination ou d’halogénation. / Fluidic devices offer industrial advantages especially in terms of security due to a better thermal control and a minimization of risks with lower volumes involved. This technology increases chemical reaction efficiencies thanks to a more homogeneous system which affects yields, selectivity and reagent quantities. Nowadays, pharmaceutical active principles are still predominantly produced using batch. Thus, in a first part, microfluidic has been applied to the synthesis of an active pharmaceutical ingredient. Each reaction step as well as the physical parameters of the system have been optimized by using a micromixer. A multi-step process has been developed with a productivity up to 100 g.h-1. Productions have been realized thereby validating preliminary studies including the possibility to produce the active pharmaceutical ingredient.Boron derivatives are chemical intermediates commonly used in organic synthesis for their reactivity. In a second part, electrophilic borylation reaction has been studied with the synthesis of oxa and azaborinins compounds as targets and the use of diisopropylamine borane complex (DIPAB) as a borylation agent. These molecules have then been functionalized through the use of oxidation, amination or halogenation reactions.