title: Regioselective Spirostan E-Ring Opening for the Synthesis of Dihydropyran Steroidal Frameworks.
abstract: The regioselective opening of the ring E in spirostan sapogenins provides new dihydropyran derivatives. This novel side chain is obtained after a Lewis acid mediated acetolysis followed by an alkaline workup. The reaction mechanism is analyzed via density functional theory computations, and both experimental and computational data support the formation of an oxacarbenium intermediate. The behavior of the title skeletons under acidic conditions is also investigated.
authors.affiliation: Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados , Unidad Mérida, Km 6 Antigua Carretera a Progreso, Apdo, Postal 73, Cordemex, Mérida, Yucatán 97310, México.
authors.forename: J Ciciolil
authors.initials: JC
authors.lastname: Hilario-Martínez
authors.affiliation: Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados , Unidad Mérida, Km 6 Antigua Carretera a Progreso, Apdo, Postal 73, Cordemex, Mérida, Yucatán 97310, México.
authors.forename: Reyna
authors.initials: R
authors.lastname: Zeferino-Díaz
authors.affiliation: Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos , Av Universidad 1001, Cuernavaca, Morelos C. P. 62209, México.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Muñoz-Hernández
authors.forename: Ma Guadalupe
authors.initials: MG
authors.lastname: Hernández-Linares
authors.affiliation: Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados , Unidad Mérida, Km 6 Antigua Carretera a Progreso, Apdo, Postal 73, Cordemex, Mérida, Yucatán 97310, México.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Cabellos
authors.affiliation: Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados , Unidad Mérida, Km 6 Antigua Carretera a Progreso, Apdo, Postal 73, Cordemex, Mérida, Yucatán 97310, México.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Merino
authors.forename: Jesús
authors.initials: J
authors.lastname: Sandoval-Ramírez
authors.affiliation: Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, The University of Iowa , Iowa City, Iowa 52242, United States.
authors.forename: Zhendong
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados , Unidad Mérida, Km 6 Antigua Carretera a Progreso, Apdo, Postal 73, Cordemex, Mérida, Yucatán 97310, México.
authors.forename: María A
authors.initials: MA
authors.lastname: Fernández-Herrera
mesh_terms: D058116:Lewis Acids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011714:Pyrans / Q000737:chemistry*; D013150:Spirostans / Q000737:chemistry*; D013237:Stereoisomerism; D013256:Steroids / Q000737:chemistry
chemical_list: D058116:Lewis Acids; D011714:Pyrans; D013150:Spirostans; D013256:Steroids