Stereoselective reactions of 16-Methylene 19-Norsteroids

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dc.contributor.advisorBull, James Ren_ZA
dc.contributor.authorKaiser, Delene Anneen_ZA
dc.date.accessioned2016-10-14T06:27:22Z
dc.date.available2016-10-14T06:27:22Z
dc.date.issued1991en_ZA
dc.description.abstractThe influence of the 17-substituent upon epoxidation of 3-methoxy-16-methylene-estra- 1,3,5(10)-trien-17-one and the derived 17β-hydroxy and 17β-acetoxy compounds was investigated. Alkaline hydrogen peroxide epoxidation of 3-methoxy-16-methyleneestra- 1,3,5(10)-trien-17-one occurred in good yields, but poor stereoselectivity was obtained due to mechanistic considerations. Poor stereoselectivity was also obtained for the peracid epoxidation of 3-methoxy-16-methylene-estra-1,3,5(10)-trien-17β-ol, due to the pseudo-equatorial position of the 17β-hydroxyl group. However, excellent stereoselectivity was obtained using Sharpless conditions (vanadium catalyst), which gave only the epoxide syn to the hydroxyl group, in good yields. Surprisingly, peracid epoxidation of 3-methoxy-16-methylene-estra-1,3,5(10)-trien-17β-yl acetate favoured equatorial attack resulting in a 2:1 ratio of the (16R)- and (16S)-epoxide isomers, instead of the expected axial approach by the peracid.en_ZA
dc.identifier.apacitationKaiser, D. A. (1991). <i>Stereoselective reactions of 16-Methylene 19-Norsteroids</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Chemistry. Retrieved from http://hdl.handle.net/11427/22136en_ZA
dc.identifier.chicagocitationKaiser, Delene Anne. <i>"Stereoselective reactions of 16-Methylene 19-Norsteroids."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Chemistry, 1991. http://hdl.handle.net/11427/22136en_ZA
dc.identifier.citationKaiser, D. 1991. Stereoselective reactions of 16-Methylene 19-Norsteroids. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Kaiser, Delene Anne AB - The influence of the 17-substituent upon epoxidation of 3-methoxy-16-methylene-estra- 1,3,5(10)-trien-17-one and the derived 17β-hydroxy and 17β-acetoxy compounds was investigated. Alkaline hydrogen peroxide epoxidation of 3-methoxy-16-methyleneestra- 1,3,5(10)-trien-17-one occurred in good yields, but poor stereoselectivity was obtained due to mechanistic considerations. Poor stereoselectivity was also obtained for the peracid epoxidation of 3-methoxy-16-methylene-estra-1,3,5(10)-trien-17β-ol, due to the pseudo-equatorial position of the 17β-hydroxyl group. However, excellent stereoselectivity was obtained using Sharpless conditions (vanadium catalyst), which gave only the epoxide syn to the hydroxyl group, in good yields. Surprisingly, peracid epoxidation of 3-methoxy-16-methylene-estra-1,3,5(10)-trien-17β-yl acetate favoured equatorial attack resulting in a 2:1 ratio of the (16R)- and (16S)-epoxide isomers, instead of the expected axial approach by the peracid. DA - 1991 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1991 T1 - Stereoselective reactions of 16-Methylene 19-Norsteroids TI - Stereoselective reactions of 16-Methylene 19-Norsteroids UR - http://hdl.handle.net/11427/22136 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/22136
dc.identifier.vancouvercitationKaiser DA. Stereoselective reactions of 16-Methylene 19-Norsteroids. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Chemistry, 1991 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/22136en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemistryen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherChemistryen_ZA
dc.titleStereoselective reactions of 16-Methylene 19-Norsteroidsen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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