RT info:eu-repo/semantics/doctoralThesis T1 Studies towards the stereoselective synthesis of 6-membered oxacycles A1 Fernández Peña, Laura A2 Universidad de Valladolid. Escuela de Doctorado K1 Heterociclos K1 Synthesis K1 Síntesis K1 Stereoselective K1 Estereoselectiva K1 Heterocycles K1 Heterociclos K1 2306 Química Orgánica AB Heterocycles, particularly 6-membered oxacycles, are common scaffolds in pharmacologically and biologically active compounds. Consequently, the development of new methodologies for their synthesis is always required. In this sense, Prins cyclization and its variant, silyl-Prins cyclization, have emerged as useful tools for the synthesis of various types of heterocyclic products. On the other hand, organosilicon compounds are valuable synthetic intermediates due to the unique properties conferred by the silicon atom to the substrates. In this project, leveraging these properties, we aim to establish new synthetic methodologies for the synthesis of 6-membered oxacycles.Firstly, we focused on the synthesis of dihydropyran derivatives through silyl-Prins cyclization of Z-vinylsilyl alcohols. After obtaining the desired starting materials, we established a methodology that enabled the synthesis of 2,6-cis-disubstituted dihydropyrans, using substituents of different nature in both the aldehyde and the alcohol. Likewise, this procedure was applied to obtain two analogues of naturalproducts.Then, we decided to study the use of terminal cyclopropylsilyl alcohols to synthesize 2,4,6-cis-3-trans-tetrasubstituted tetrahydropyrans through Prins cyclization. Different C-4-halogenated tetrahydropyrans were obtained in good to high yields and with excellent diastereoselectivity, using various aldehydes and different halogenating agents.Finally, we envisioned the use of ketones as electrophiles in Prins cyclization of terminal cyclopropylsilyl alcohols. Symmetric and unsymmetric ketones provided the desired polisusbtituted 4-iodo- and 4-bromo-tetrahydropyrans and spiro-tetrahydropyrans in good yields. Additionally, the use of unsymmetric ketones demostrated good stereoselectivity, predominantly forming a major C-2 epimeric tetrahydropyran derivatives. YR 2024 FD 2024 LK https://uvadoc.uva.es/handle/10324/70259 UL https://uvadoc.uva.es/handle/10324/70259 LA eng NO Escuela de Doctorado DS UVaDOC RD 22-nov-2024