Ansamycin natural products have historically been a rich source of new drugs for the treatment of bacterial infections and cancer. The C17-benzene ansamycins in particular have shown excellent preclinical results as potential anti-fungal and anti-cancer medicines. However, their thorough clinical evaluation has been hampered by the absence of a concise synthetic strategy. In order to address this issue, recently developed hydrogenative carbon-carbon bond forming methods were applied toward a short total synthesis of C17-benzene ansamycins. This class of natural products provides a challenging testing ground for these methods while facilitating the further development of compounds which may be used as treatments for life threatening diseases. In the first synthetic approach to the C17-benzene ansamycins key bond formations include direct iridium catalyzed carbonyl crotylation from the alcohol oxidation level followed by chelation-controlled dienylation to form the stereotriad, which is attached to the arene via Suzuki cross-coupling. The diene-containing carboxylic acid is prepared using rhodium catalyzed acetylene-aldehyde reductive C-C coupling mediated by gaseous hydrogen. Finally, ring-closing metathesis delivers the cytotrienin core. The second approach toward triene-containing C17-benzene ansamycins resulted in the syntheses of trienomycins A and F, which were prepared in 16 steps (longest linear sequence) and 28 total steps. The C11-C13 stereotriad was generated via enantioselective ruthenium-catalyzed alcohol CH syn crotylation followed by chelation-controlled carbonyl dienylation. Finally, diene-diene ring closing metathesis to form the macrocycle. The present approach is 14 steps shorter (LLS) than the prior syntheses of trienomycins A and F, and eight steps shorter than any prior synthesis of a triene-containing C17-benzene ansamycin. / text

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23734号 / 理博第4824号 / 新制||理||1690(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 時任 宣博 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Dans ce manuscrit, une voie atome économique d'un robuste amphiphile polyols à base de alkyle chaîne liée à liaison C-C ont été développés, ce qui est plus stable pour des applications plus larges. Ce processus implique l'utilisation de matières premières renouvelables et relativement peu coûteuses. Des cétoses tels que la 1,3-dihydroxyacétone et le D-fructose ont été utilisés comme substrats avec des aldéhydes comme agents d'alkylation sans aucune étape de protection-déprotection. La synthèse a été divisée en deux étapes, dans la première étape, les cétoses déprotonées réagissent avec les électrophiles aldéhydes pour former les intermédiaires hydroxycétones. Ensuite, une seconde étape d'hydrogénation avec un catalyseur du ruthénium sur alumine sous pression d'hydrogène a donné accès aux polyols alkylés. Le rendement global de ce procédé en deux étapes est modéré compte tenu de la difficulté de faire réagir une partie fortement hydrophobe avec une partie fortement hydrophile. Ensuite, ces adduits de tétraols obtenus avec la 1,3-dihydroxyacétone ont également été évalués en tant que tensioactifs en effectuant des tests physico-chimiques (CMC, point Krafft et Phase Inverse Temperature). Les résultats ont montré que ces nouveaux agents tensioactifs liés à la liaison C-C sont aussi efficaces que d'autres agents tensioactifs disponibles dans le commerce en diminuant la tension de surface, ce qui est une propriété très attrayante pour des applications potentielles / In this manuscript, an atom economic route of C-C bond based surfactants has been developed. They are more stable for broader applications. This process involves the use of renewable and relatively low cost raw materials. Ketoses such as 1,3-dihydroxyacetone and D-fructose were used as substrates with aldehydes as alkylation agents without any protection-deprotection step. The synthesis has been divided into two steps, in the first step the deprotonated ketoses react with the aldehydes electrophiles to form the hydroxyketone intermediates. Then, a second step of hydrogenation with Ruthenium on alumina catalyst under hydrogen pressure gave access to the alkylated polyols. The overall yield of this two-step process is moderate considering the difficulty of reacting a highly hydrophobic part with a highly hydrophilic part. Then these tetraols adducts obtained with 1,3-dihydrdoxyacetone were also evaluated as surfactants by making physico-chemical tests (CMC, Krafft point and Phase Inverse Temperature). Results have exhibited this novel C-C bond connected surfactants perform as efficient as other commercially available surfactants in decreasing the surface tension which is a very attractive property for potential applications