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We successfully introduced up to 12 poly(benzyl ether)dendron-thiols of the second generation (D2SH) into the Au13 core of [Au23(ScC6H11)16]- while retaining the geometric structure. The decoration with D2SH enhanced the optical absorbance in the >2.5 eV region and the quantum yield of photoluminescence at ∼1.6 eV by ∼15 times.

Two series of N-methyliminodiacetic acid (MIDA) boronates were prepared and their mesomorphic properties were investigated. MIDA-substituted benzoic acid esters were synthesized via the Mitsunobu reaction. The second series of MIDA benzyl ether derivatives was prepared via Williamson etherification and subsequent borylation. Both series exhibit smectic A (SmA) phases. In the case of MIDA boronate esters, a substitution with perfluorinated side chains led to increased transition temperatures and broadening of the SmA phases. The phase geometries of the mesophases were determined by X-ray diffraction. Quantum-chemical calculations provided further insight into the packing model.

Stereoselective formation of glycosidic linkages has been the prime focus for contemporary carbohydrate chemistry. Herein, we report cyanomethyl (CNMe) ether as an efficient and effective participa...

Hypercrosslinked polymers were produced via the self-condensation of benzyl ether compounds, providing a one-component route to highly porous networks and significant reductions in catalyst waste compared to conventional routes. These compounds also represent a new class of external crosslinkers, able to impart improved textural properties when compared to standard aliphatic crosslinkers.

Esta Tesis está centrada en el desarrollo de nuevas metodologías en Síntesis Orgánica mediante la utilización de compuestos organometálicos. El hilo conductor es la -litiación selectiva de distintos aril bencil éteres, demostrándose que los intermedios organolíticos así generados pueden mantenerse estables frente al reagrupamiento [1,2] de Wittig permitiendo su funcionalización posterior. Mediante el estudio en profundidad del comportamiento de los aril -litiobencil éteres frente a dicho reagrupamiento se ha encontrado que dos mecanismos distintos, uno radicalario y otro aniónico concertado, pueden coexistir. Asimismo, hemos descrito la carbolitiación intramolecular de o-(alquinil)fenil bencil éteres, mediante una adición anti al triple enlace, pudiéndose sintetizar interesantes heterociclos de 5 eslabones. Finalmente, también se ha demostrado el potencial del grupo -litiobenciloxilo como grupo orto-director de la metalación. Los objetivos abordados en esta Tesis han dado lugar a la preparación de una amplia variedad de moléculas que presentan interés por sus potenciales actividades biológicas y/o farmacológicas.

Pd-catalyzed C(sp3)-H activation of alcohol typically shows β-selectivity due to the required distance between the chelating atom in the attached directing group and the targeted C-H bonds. Herein we report the design of a hemilabile directing group which exploits the chelation of a readily removable benzyl ether moiety to direct γ- or δ-C-H carbonylation and olefination of alcohols. The utility of this approach is also demonstrated in the late-stage C-H functionalization of β-estradiol to rapidly prepare desired analogues that required multi-step syntheses with classical methods.

The metal organic frameworks material (CuOBA) was synthesized by solvothermal method. The physicochemical characteristics of this solid catalyst were determined by a number of different analytical techniques including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FT-IR). The CuOBA was used as a heterogeneous catalyst for the coupling reaction of C=O connection between 5’- bromo - 2’-hydroxiacetophenone and benzyl ether in good conversion. The effects of time, temperature, concentration of reactants, solvents, and mass of catalyst were surveyed. The results revealed that CuOBA is used as a catalyst for organic reactions with conversion of 87%, and the solid catalyst could be recovered six times without a significant degradation in catalytic activity.

Pentafluorosulfanyl chloride (SF5Cl) is the most prevalent pentafluorosulfanylating agent. However, its compatibility with common solvents has not been evaluated. Thus, in order to provide a qualitative guide for the use of SF5Cl, we report a systematic evaluation of its compatibility in various organic solvents and water via the well-established SF5Cl radical addition on an alkene, using allyl benzyl ether as the model substrate. Solvent and reaction temperature comparison, as well as a robustness screen have been performed and will be discussed.

Herein, we report a poly(benzyl ether)-based self-immolative polymer (SIP) with pendant pyridine disulfide groups. Cleavage of the side-chain disulfides leads to the formation of phenolates, which initiate depolymerization from the side chain. Due to the higher density of the disulfide groups compared to that of the chain-end-capping group, which normally is responsible for initiating depolymerization of SIPs, the side chain-immolative polymer (ScIP) can be readily degraded in the solid state where the mobility of polymer chains is substantially limited. The ScIP was also further modified through the thiol–disulfide exchange reaction to prepare ScIP-g-poly(ethylene glycol) graft polymers and organogels, which were also able to undergo complete reductive self-immolative degradation.

To achieve high-performance thermosets from renewable resources, six acetovanillone-derived poly(aryl ether)s (two with the acetic moiety, two with the phenyl methacrylic moiety, and two with the vinyl benzyl ether moiety) were prepared. The poly(aryl ether)s with acetic- or phenyl methacrylic moiety were applied as epoxy curing agents to cure with a phenol-dicyclopentadiene epoxy resin (HP7200). The Tg values of the resulting epoxy thermosets range from 228 to 252 °C (DMA data) and the dielectric constants range from 2.78 to 3.01 U (at 3 GHz). The two poly(aryl ether)s with vinyl benzyl ether moiety were self-cured to high-performance thermosets with Tg values of 255 and 293 °C (DMA data) and with a dielectric constant of 2.89 and 2.68 U (at 3 GHz), respectively. This work successfully demonstrates a strategy to achieve high-performance thermosets from reactive polyethers, which are derived from renewable acetovanillone.

Supramolecular orientational memory (SOM) provides a route to otherwise inaccessible nanoscale architectures for certain molecules. In these privileged cases, columnar domains organized from self-assembling dendrons undergo reorientation during heating to, and subsequent cooling from, a 3D phase composed of “spheres”, such as a body-centered cubic phase or a Pmn cubic phase, known also as Frank-Kasper A15. The directions of the reoriented columns preserve key interactions from the preceding cubic phase. However, SOM was observed so far in a very limited number of assemblies. The molecular determinants enabling SOM, and its generality, remain poorly understood. Here we report the synthesis and structural and retrostructural analysis of a perylene bisimide (PBI) with two self-assembling benzyl ether dendrons, 3,5-G2-PBI, and compare its assemblies with those of a previously reported PBI, 3,4,5-G2-PBI, which exhibits SOM and has an additional minidendritic building block in its dendrons. The removal of this minidendron in 3,5-G2-PBI eliminates its ability to self-assemble into supramolecular spheres and organize into a cubic phase, thereby precluding 3,5-G2-PBI from exhibiting SOM. This finding demonstrates hierarchical transfer of structural information from primary structure to material function, analogous to the misfolding of proteins into toxic structures such as those implicated in Alzheimer's and Prion diseases. The concepts exemplified here provide new insights into the hierarchical basis for SOM and will aid in the translation of the SOM concept to a broader diversity of soft matter such as block copolymers and surfactants.

A new protocol for the anti-Markovnikov hydrofunctionalization of alkenyl alcohol O-Bn ethers was developed using xanthates as functionalizing agents in the presence of lauroyl peroxide as a radical initiator and a stoichiometric oxidant. The benzyl group serves as a traceless hydrogen donor in the remote radical hydrogen atom transfer event during the process. Ministry of Education (MOE) Nanyang Technological University Accepted version This work was supported by funding from Nanyang Technological University (for S. C.), the Singapore Ministry of Education (Academic Research Fund Tier 1: RG2/15 for S. C.) and the Natural Sciences and Engineering Research Council (for F. G.). F. G. and S. C. are grateful to the PHC Merlion grant (Project 5.02.15) for the support of this collaboration project.