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 10-nov-2024