京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21127号 / 工博第4491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 村上 正浩, 教授 吉田 潤一, 教授 中尾 佳亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20944号 / 理博第4396号 / 新制||理||1631(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 丸岡 啓二, 教授 大須賀 篤弘 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21776号 / 工博第4593号 / 新制||工||1716(附属図書館) / 京都大学大学院工学研究科材料化学専攻 / (主査)教授 中尾 佳亮, 教授 松原 誠二郎, 教授 杉野目 道紀 / 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(工学) / 甲第21796号 / 工博第4613号 / 新制||工||1718(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 村上 正浩, 教授 松田 建児, 教授 中尾 佳亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

No description available.

No description available.

The development of new strategies and associated reagents that enable previously inaccessible synthetic disconnections is largely attributing to the remarkable progress in exploring new chemical space for drug discovery and innovative complex molecule syntheses. In the Wengryniuk laboratory, we are devoted to discovering new synthetic methodologies that are based on umpolung or reverse polarity, strategies, enabled by Nitrogen-ligated (bis)cationic hypervalent iodine reagents (N-HVIs). I(III) N-HVIs represent an attractive new class of oxidant as they are environmentally benign, highly tunable, and have shown ability in enabling distinguished modes of reactivity. This dissertation focuses on demonstrating the synthetic utility of these N-HVI reagents towards C–O bond formation via a reverse polarity approach.In Chapter 1, a summary of the reactivity and characteristics of hypervalent iodine reagents is provided. Chapter 2 describes a mild and metal-free strategy for alcohol oxidation mediated by I(III) N-HVI reagents. This method demonstrates the first method for chemoselective oxidation of equatorial over axial alcohols and was the first in situ synthesis and application of N-HVIs for a simple one-pot procedure. Chapter 3 discusses a novel strategy for a dual C–H functionalization to access functionalized chroman scaffolds via an umpolung oxygen activation cyclization cascade. Computational studies in collaboration with Prof. Dean Tantillo (UC-Davis) along with experimental probes in our laboratory, support the formation of an umpoled oxygen intermediate as well as competitive direct and spirocyclization pathways for the key C–O bond forming event. The utility of the developed method is demonstrated through a downstream derivatization of the iodonium salt moiety to access C–H, C–X, and C–C substitution via established Pd-catalyzed cross couplings. Total synthesis of (±)-conicol natural product was performed in 8 steps and 23% overall yield, further demonstrating the synthetic utility of the developed method. Key synthetic steps include a smooth construction of the chroman core via N-HVI mediated C–H etherification of a pendant alcohol followed by a late-stage double bond installation. Overall, this dissertation summarizes the current state of research enabled by N-HVI reagents, with a focus on their utility in reverse polarity heteroatom activation strategies, and it serves as a practical guide for future development in the field. / Chemistry

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24432号 / 理博第4931号 / 新制||理||1704(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 若宮 淳志, 教授 畠山 琢次 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24148号 / 工博第5035号 / 新制||工||1786(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 杉野目 道紀, 教授 大江 浩一, 教授 中尾 佳亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The reaction barrier and heat of formation of the various dehydrogenation reactions involved in the steam reforming of ethane is a critical concern in the applications and understanding of these reactions. Focusing on Ir-based catalyst, we report a comprehensive reaction network of dehydrogenation of ethane on Ir(100) based on extensive density functional theory calculations performed on 10 C-H bond cleavage reactions, utilizing the Vienna Ab Initio Package codes. The geometric and electronic structures of the adsorption of C2Hx species with corresponding transition-state structures is reported. We found that the C-H bond in CH3C required the most energy to activate, due to the most stable four-fold hollow adsorption site configuration. Ethane can easily dissociate to CH3CH and CH2CH2 on Ir(100) and further investigation of surface temperature dependence will contribute to the research effort in this area. By using the degree of dehydrogenation of the reactant species as a variable to correlate the C-H bond cleavage barrier as well as reaction energy. DFT studies reveal that the surface Ir(100) to a great extent promotes ethane dehydrogenation when compared to other surfaces.