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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Autores principales: Di Nardo, C., Varela, O., de Lederkremer, R.M., Baggio, R.F., Vega, D.R., Garland, M.T.
Formato: JOUR
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00086215_v269_n1_p99_DiNardo
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spelling 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 AT dinardoc brominationofsugarenonesandenonolactones
AT varelao brominationofsugarenonesandenonolactones
AT delederkremerrm brominationofsugarenonesandenonolactones
AT baggiorf brominationofsugarenonesandenonolactones
AT vegadr brominationofsugarenonesandenonolactones
AT garlandmt brominationofsugarenonesandenonolactones
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