Bromination of sugar enones and enonolactones
Bromination of 2,4,6-tri-O-benzoyl-3-deoxy-d-erytro-hex-2-enono-1,5-lactone (1) took place diastereoselectively to afford a single product: 2,4,6-tri-O-benzoyl-2,3-dibromo-3-deoxy-d-altrono-1,5-lactone (2). The configuration of C-2 and C-3 was determined as R,R by NMR spectroscopy and taking into ac...
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todo:paper_00086215_v269_n1_p99_DiNardo2023-10-03T14:06:39Z Bromination of sugar enones and enonolactones Di Nardo, C. Varela, O. de Lederkremer, R.M. Baggio, R.F. Vega, D.R. Garland, M.T. Bromination Enones Enonolactones Sugar enones and enonolactones carbohydrate derivative organobromine derivative article bromination nuclear magnetic resonance priority journal reaction analysis stereochemistry X ray diffraction Bromination of 2,4,6-tri-O-benzoyl-3-deoxy-d-erytro-hex-2-enono-1,5-lactone (1) took place diastereoselectively to afford a single product: 2,4,6-tri-O-benzoyl-2,3-dibromo-3-deoxy-d-altrono-1,5-lactone (2). The configuration of C-2 and C-3 was determined as R,R by NMR spectroscopy and taking into account considerations of the stereochemical course of the bromination. The configuration of 2 was confirmed by X-ray analysis, which also revealed that the conformation of the lactone ring consists of a 4H3(d) distorted half-chair. The bromine addition to 2,5,6,7-tetra-O-benzoyl-d-arabino-hept-2-enono-1,4-lactone (5), readily prepared by DBU-promoted elimination from the perbenzoylated lactone derivative 4, was also diastereoselective and led to the dibromo derivative 6, whose configuration for C-2 and C-3 was assigned as S,S. Bromination of the α,β-unsaturated carbonyl system of 2-propyl 6-O-acetyl-3,4-dideoxy-α-d-glycero-hex-3-enopyranosid-2-ulose (7) afforded an unsaturated monobromo derivative: 2-propyl 6-O-acetyl-3-bromo-3,4-dideoxy-α-d-glycero-hex-3-enopyranosid-2-ulose (8), suggesting that dehydrobromination occurred after addition of bromine. © 1995. Fil:Di Nardo, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Varela, O. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:de Lederkremer, R.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00086215_v269_n1_p99_DiNardo |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Bromination Enones Enonolactones Sugar enones and enonolactones carbohydrate derivative organobromine derivative article bromination nuclear magnetic resonance priority journal reaction analysis stereochemistry X ray diffraction |
| spellingShingle |
Bromination Enones Enonolactones Sugar enones and enonolactones carbohydrate derivative organobromine derivative article bromination nuclear magnetic resonance priority journal reaction analysis stereochemistry X ray diffraction Di Nardo, C. Varela, O. de Lederkremer, R.M. Baggio, R.F. Vega, D.R. Garland, M.T. Bromination of sugar enones and enonolactones |
| topic_facet |
Bromination Enones Enonolactones Sugar enones and enonolactones carbohydrate derivative organobromine derivative article bromination nuclear magnetic resonance priority journal reaction analysis stereochemistry X ray diffraction |
| description |
Bromination of 2,4,6-tri-O-benzoyl-3-deoxy-d-erytro-hex-2-enono-1,5-lactone (1) took place diastereoselectively to afford a single product: 2,4,6-tri-O-benzoyl-2,3-dibromo-3-deoxy-d-altrono-1,5-lactone (2). The configuration of C-2 and C-3 was determined as R,R by NMR spectroscopy and taking into account considerations of the stereochemical course of the bromination. The configuration of 2 was confirmed by X-ray analysis, which also revealed that the conformation of the lactone ring consists of a 4H3(d) distorted half-chair. The bromine addition to 2,5,6,7-tetra-O-benzoyl-d-arabino-hept-2-enono-1,4-lactone (5), readily prepared by DBU-promoted elimination from the perbenzoylated lactone derivative 4, was also diastereoselective and led to the dibromo derivative 6, whose configuration for C-2 and C-3 was assigned as S,S. Bromination of the α,β-unsaturated carbonyl system of 2-propyl 6-O-acetyl-3,4-dideoxy-α-d-glycero-hex-3-enopyranosid-2-ulose (7) afforded an unsaturated monobromo derivative: 2-propyl 6-O-acetyl-3-bromo-3,4-dideoxy-α-d-glycero-hex-3-enopyranosid-2-ulose (8), suggesting that dehydrobromination occurred after addition of bromine. © 1995. |
| format |
JOUR |
| author |
Di Nardo, C. Varela, O. de Lederkremer, R.M. Baggio, R.F. Vega, D.R. Garland, M.T. |
| author_facet |
Di Nardo, C. Varela, O. de Lederkremer, R.M. Baggio, R.F. Vega, D.R. Garland, M.T. |
| author_sort |
Di Nardo, C. |
| title |
Bromination of sugar enones and enonolactones |
| title_short |
Bromination of sugar enones and enonolactones |
| title_full |
Bromination of sugar enones and enonolactones |
| title_fullStr |
Bromination of sugar enones and enonolactones |
| title_full_unstemmed |
Bromination of sugar enones and enonolactones |
| title_sort |
bromination of sugar enones and enonolactones |
| url |
http://hdl.handle.net/20.500.12110/paper_00086215_v269_n1_p99_DiNardo |
| work_keys_str_mv |
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| _version_ |
1807324463091417088 |