Thesis advisor: James P. Morken / This dissertation describes the development of various palladium-catalyzed syntheses of organoboron compounds with the 1,2-metallate shift of organoboron “ate” complexes as a common mechanistic feature. Chapter one discusses the history of the 1,2-metallate shift with a focus on reactions promoted by transition metals, followed by my work on the palladium-catalyzed, enantioselective, halide-tolerant conjunctive cross-coupling reaction to enable the use of Grignard reagents and arylbromides. Chapter two discusses the attempt to engage allylic electrophiles in the conjunctive cross-coupling reaction and the discovery and optimization of the vinylidenation reaction to access 1,1-disubstituted boryl alkenes. Unlike other palladium-catalyzed reactions that proceed by a 1,2-metallate shift, the vinylidenation proceeds by a β-hydride elimination rather than a reductive elimination as the final step in the catalytic cycle. Chapter three discusses the development of the enantioselective conjunctive cross-coupling of propargylic electrophiles to access enantioenriched β-boryl allenes. Methanol additive was found to improve both the yield and enantioselectivity of the reaction. 1H NMR studies show that methanol exchanges with the pinacol ligand on the boron “ate” complex. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Polymers with intrinsic microporosity (PIMs) showed the potential to provide highly permeable and highly selective membranes for gas separation applications with the ability to fine-tune their properties for better performance. The concept of microporosity was extended to the polyimides by using kinked, contorted and stable structures to obtain high gas performance combined with excellent solution-processability, high thermal stability, and a unique platform for a wide range of possible modifications and tunability. Thus, studying the structure-property relationships is a critical key to develop advanced materials that can replace the commercially available membranes like cellulose acetate and Matrimid. Importantly, in the microporous polyimides (PIM-PIs) system, varying the type of the side chains appended to the diamines or dianhydrides impacts polymeric membrane properties, and in turn, gas separation performance. In this dissertation, we have examined the effect of ring substitutes, incorporated into novel polyimides backbones, on polymer properties and gas separation performance. The choice of side group can induce subtle changes in material properties and molecular interactions between the polymeric chains and affect the pore-size distribution, chain packing and yielding distinct combination between gas permeability and permselectivity. We have shown that the effect of tertiary amine groups, in polyimide structures, on the CO2 solubility is marginal but it can control the chain packing. However, introducing bromine groups on the polymer backbone can boost the O2 permeability and O2/N2 selectivity and perform better than the commercially available membranes. BCBr4-SBIDA demonstrated the same O2/N2 selectivity relative to cellulose acetate but approximately 10-fold higher gas permeability. Combining high selectivity with good permeability was achieved by a newly designed carboxyl-functionalized homopolymer (6FDA-TrMPD) with CO2 permeability of 144 barrer and CO2/CH4 selectivity of 45. The new W-shaped CANAL diamines, prepared by one-step synthesis, were used as microporosity generators in polyimides and revealed promising gas transport performance with the same selectivity relative to cellulose acetate by 23-fold higher permeability (CANAL-PI-3-MeNH2). Therefore, developing advanced polymers for membrane-based gas separation can be obtained by an ideal combination between kinked monomers, side chains, and stable materials.

La modification des propriétés du graphène, notamment l’ouverture d’une bande interdite par la nanostructuration, est un véritable enjeu pour la physique et pour les applications du graphène. La nanostructuration peut se faire suivant l’approche « top-down » ou « bottom-up ». Au cours de cette thèse nous nous sommes intéressés à la seconde approche. L’approche « bottom-up » permet de contrôler à l’atome près la structure des matériaux. L’objectif de cette thèse est de fabriquer par synthèse chimique des boites quantiques de graphène et des motifs graphéniques contenant un réseau périodique de trous (nanomesh) et d’en étudier les propriétés physiques. Dans une première partie, une « famille » de nanoparticules de graphène a été préparée par synthèse organique via des réactions de Diels-Alder et de Scholl et les propriétés optiques ont été étudiées sur des solutions et à l’échelle de la molécule unique. Dans une deuxième partie, un nouveau type de structures graphéniques intermédiaires entre les boites quantiques et les nanorubans, des nano-bâtonnets de graphène (nanorods) ont été synthétisés. Enfin, plusieurs précurseurs ont été synthétisés pour la réalisation de nanomeshs de graphène. Ces précurseurs permettront d’obtenir, en utilisant le dépôt chimique en phase vapeur dans la chambre d’un microscope à effet tunnel, des nanomesh de graphène présentant des structures différentes. / The manipulation of the electronic properties of graphene, and in particular the bandgap opening by nano-patterning, is a crucial issue for both physics and applications. The nanostructuration can be done either through the top-down approach or the bottom-up approach. This bottom-up approach allows controlling at the atomic level the structure of the materials. The aim of this thesis is to prepare graphene quantum dots and graphene nanomeshes (regular arrays of holes in a graphene sheet) by chemical synthesis, and to study their physical properties. In the first part, a “family” of graphene quantum dots was prepared with organic chemistry via Diels-Alder and Scholl reactions and the optical properties were studied both in solution and at the single molecule scale. In the second part, a new type of graphenic structures intermediate between quantum dots and nanoribbons were synthesized and we named them “graphene nanorods”. These objects are one dimensional but have a controlled length compared to nanoribbons prepared via polymerization. Finally, various precursors were synthesized to create graphene nanomeshes. These precursors will allow the formation, using chemical vapor deposition in a scanning tunneling microscope chamber, of nanomeshes exhibiting different structures and morphology.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21128号 / 工博第4492号 / 新制||工||1698(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 吉田 潤一, 教授 杉野目 道紀, 教授 松田 建児 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第21043号 / 薬科博第86号 / 新制||薬科||9(附属図書館) / 京都大学大学院薬学研究科薬科学専攻 / (主査)教授 高須 清誠, 教授 竹本 佳司, 教授 大野 浩章 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM

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Yes / Marrying synthetic biology with synthetic chemistry provides a powerful approach toward natural product diversification, combining the best of both worlds: expediency and synthetic capability of biogenic pathways and chemical diversity enabled by organic synthesis. Biosynthetic pathway engineering can be employed to insert a chemically orthogonal tag into a complex natural scaffold affording the possibility of site-selective modification without employing protecting group strategies. Here we show that, by installing a sufficiently reactive handle (e.g., a C–Br bond) and developing compatible mild aqueous chemistries, synchronous biosynthesis of the tagged metabolite and its subsequent chemical modification in living culture can be achieved. This approach can potentially enable many new applications: for example, assay of directed evolution of enzymes catalyzing halo-metabolite biosynthesis in living cells or generating and following the fate of tagged metabolites and biomolecules in living systems. We report synthetic biological access to new-to-nature bromo-metabolites and the concomitant biorthogonal cross-coupling of halo-metabolites in living cultures. / European Research Council under the European Union’s Seventh Framework Programme (FP7/2007–2013/ERC consolidator grant GCGXC grant agreement no 614779) and ERAIB (Grant no. 031A338A) and H2020-MSCA-IF-2014 Grant no. 659399

The work disclosed in this dissertation outlines a newly discovered acidic alumina-mediated orthoallylation of unprotected phenols and the application of this method to the synthesis of prenylated phenolic natural products including dorsmanin A and hyperbeanol Q. Chapter 1 consists of a literature review of prenylated phenolic compounds and includes a discussion of their biological significance followed by an extensive review of the various synthetic strategies that have been used to prepare them. It is our intention to publish the content of this chapter as a review article for the synthetic chemistry community. Showcased in Chapter 2 is the optimization of a novel prenylation method via acidic alumina as the promoter. Phenols and allyl alcohols are combined with acidic alumina in 1,2-dichloroethane or acetonitrile to induce a proposed coordination of the substrates to the alumina surface via hydrogen bonding which facilitates the regioselective ortho-prenylation of phenols. The extensive substrate scope of this chemistry is discussed. In Chapter 3, this alumina-mediated prenylation is applied to the syntheses of several acylphloroglucinol natural products and unnatural structural analogues which are evaluated for their antimicrobial and anthelmintic (anti-parasitic) activity. Some of these compounds exhibited antimicrobial activity and some exhibited anthelmintic potential. In Chapter 4, this prenylation strategy is further extended to the syntheses of additional prenylated phenolic natural products: (±)-sanjuanolide and dorsmanin A. Investigations towards the synthesis of HP1 are also reported. Development of the syntheses of these natural product targets provides a useful venue to investigate the scope of our alumina-mediated phenol prenylation chemistry and to identify its scope and limitations. / Thesis / Doctor of Philosophy (PhD)

<p dir="ltr">Both natural and synthetic macromolecules have gained significant attention over the last two decades as more and more applications have been developed for these types of compounds. In particular, drug delivery and sensing have seen great improvements with the use of biomimetic- and biomacromolecules. A key function for these macromolecules is selective recognition, which has evolved in nature over millions of years, but is difficult to replicate in the laboratory. An essential component of selective recognition is sequence definition of the host, which is a key characteristic found in biomolecules and is essential for the function of proteins and nucleic acids. In this work, I present new methods for creating biomimetic sequence-defined macromolecules through the synthesis of a new sequence-definable macrocycle, an amino acid-functionalized Fréchet-type sequence-defined dendrimer, and a range of new molecular cages. The molecular cages I present in this work are of varying sizes and with different endo- and exohedral functionalities intended for future use as selective recognizers.</p><p dir="ltr">The macrocycle presented in this work is the largest sequence-definable macrocycle reported to date with 20 functionalizable positions, synthesized via iterative exponential growth using a series of copper-catalyzed azide-alkyne cycloadditions (CuAACs). Synthesis of an amino acid functionalized fully sequence-defined Fréchet-type dendrimer was also attempted through a convergent synthesis via a series of CuAACs. However, in this project, I could only reach a second-generation dendron due to solubility issues. This issue should be resolvable in the future by adding solubilizing chains to the dendrons. Finally, a series of new large molecular tetrahedrons were synthesized, enabled by the development of a more facile synthesis of a previously developed vertex. This new methodology made it possible to quickly access large quantities of this key tetrahedron vertex. With the vertex, I was able to synthesize nine new molecular tetrahedrons of various sizes with pore openings of up to 33 Å and with volumes up to 17 nm³.</p>

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