Singlet-oxygen ene reaction with 3β-substituted stigmastanes. An alternative pathway for the classical Schenck rearrangement
The course of the singlet-oxygen ene reaction with stigmasta-5,22-dienes may be controlled if in the substrate a good leaving group as substituent is present at 3-C. Thus when the 5α-hydroperoxystigmasta-5,22-diene is formed instead of the well known allylic rearrangement to yield the 7α-hydroperoxy...
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_03009580_v_n11_p2351_Ponce |
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todo:paper_03009580_v_n11_p2351_Ponce2023-10-03T15:18:06Z Singlet-oxygen ene reaction with 3β-substituted stigmastanes. An alternative pathway for the classical Schenck rearrangement Ponce, M.A. Ramirez, J.A. Galagovsky, L.R. Gros, E.G. Erra-Balsells, R. Derivatives Isomers Light absorption Molecular structure Nuclear magnetic resonance spectroscopy Photochemical reactions Substitution reactions Hydroperoxystigmastadiene Intramolecular nucleophilic substitution Photosensitized oxidation Organic compounds The course of the singlet-oxygen ene reaction with stigmasta-5,22-dienes may be controlled if in the substrate a good leaving group as substituent is present at 3-C. Thus when the 5α-hydroperoxystigmasta-5,22-diene is formed instead of the well known allylic rearrangement to yield the 7α-hydroperoxystigmasta-5,22-diene isomer an intramolecular nucleophilic substitution can then occur yielding 5α-hydroxystigmasta-6,22-dien-3-one. Various stigmasta-5,22-dienes were chosen to elucidate which feature of the stigmastane is necessary to control the course of the reaction. Thus, 3β-F, 3β-Cl, 3β-Br, 3β-I and 3α-Br-stigmasta-5,22-dienes were firstly prepared and fully characterized in order to study their reaction with 1O2 under different experimental conditions. 3β-Acetoxy- and 3β-mesyloxy-stigmasta-5,22-diene derivatives were also prepared and studied. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_03009580_v_n11_p2351_Ponce |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Derivatives Isomers Light absorption Molecular structure Nuclear magnetic resonance spectroscopy Photochemical reactions Substitution reactions Hydroperoxystigmastadiene Intramolecular nucleophilic substitution Photosensitized oxidation Organic compounds |
| spellingShingle |
Derivatives Isomers Light absorption Molecular structure Nuclear magnetic resonance spectroscopy Photochemical reactions Substitution reactions Hydroperoxystigmastadiene Intramolecular nucleophilic substitution Photosensitized oxidation Organic compounds Ponce, M.A. Ramirez, J.A. Galagovsky, L.R. Gros, E.G. Erra-Balsells, R. Singlet-oxygen ene reaction with 3β-substituted stigmastanes. An alternative pathway for the classical Schenck rearrangement |
| topic_facet |
Derivatives Isomers Light absorption Molecular structure Nuclear magnetic resonance spectroscopy Photochemical reactions Substitution reactions Hydroperoxystigmastadiene Intramolecular nucleophilic substitution Photosensitized oxidation Organic compounds |
| description |
The course of the singlet-oxygen ene reaction with stigmasta-5,22-dienes may be controlled if in the substrate a good leaving group as substituent is present at 3-C. Thus when the 5α-hydroperoxystigmasta-5,22-diene is formed instead of the well known allylic rearrangement to yield the 7α-hydroperoxystigmasta-5,22-diene isomer an intramolecular nucleophilic substitution can then occur yielding 5α-hydroxystigmasta-6,22-dien-3-one. Various stigmasta-5,22-dienes were chosen to elucidate which feature of the stigmastane is necessary to control the course of the reaction. Thus, 3β-F, 3β-Cl, 3β-Br, 3β-I and 3α-Br-stigmasta-5,22-dienes were firstly prepared and fully characterized in order to study their reaction with 1O2 under different experimental conditions. 3β-Acetoxy- and 3β-mesyloxy-stigmasta-5,22-diene derivatives were also prepared and studied. |
| format |
JOUR |
| author |
Ponce, M.A. Ramirez, J.A. Galagovsky, L.R. Gros, E.G. Erra-Balsells, R. |
| author_facet |
Ponce, M.A. Ramirez, J.A. Galagovsky, L.R. Gros, E.G. Erra-Balsells, R. |
| author_sort |
Ponce, M.A. |
| title |
Singlet-oxygen ene reaction with 3β-substituted stigmastanes. An alternative pathway for the classical Schenck rearrangement |
| title_short |
Singlet-oxygen ene reaction with 3β-substituted stigmastanes. An alternative pathway for the classical Schenck rearrangement |
| title_full |
Singlet-oxygen ene reaction with 3β-substituted stigmastanes. An alternative pathway for the classical Schenck rearrangement |
| title_fullStr |
Singlet-oxygen ene reaction with 3β-substituted stigmastanes. An alternative pathway for the classical Schenck rearrangement |
| title_full_unstemmed |
Singlet-oxygen ene reaction with 3β-substituted stigmastanes. An alternative pathway for the classical Schenck rearrangement |
| title_sort |
singlet-oxygen ene reaction with 3β-substituted stigmastanes. an alternative pathway for the classical schenck rearrangement |
| url |
http://hdl.handle.net/20.500.12110/paper_03009580_v_n11_p2351_Ponce |
| work_keys_str_mv |
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| _version_ |
1782026400228704256 |