Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones

The thermal and Et 2O·BF 3-catalyzed Diels-Alder additions of 2,3-dimethylbutadiene and cyclopentadiene to (2S,6S)-6- acetoxymethyl-2-(2-propyloxy)-2H-pyran-3(6H)-one 1, derived from d-galactose, afforded the corresponding enantiomerically pure tetrahydrobenzopyrones resulting from the addition of t...

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Publicado:	2004
Materias:	1,3 butadiene 6 acetoxymethyl 2 (2 propyloxy) 2h pyran 3(6h) one 6 methyl 2 (2 propyloxy) 2h pyran 3(6h) one aldohexose alkadiene cyclopentadiene derivative galactose hexose ketone derivative Lewis acid pyran derivative unclassified drug addition reaction article carbon nuclear magnetic resonance catalysis cycloaddition diastereoisomer Diels Alder reaction enantiomer nuclear magnetic resonance spectroscopy nuclear Overhauser effect priority journal thin layer chromatography ultraviolet spectroscopy
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09574166_v15_n19_p3023_IriarteCapaccio http://hdl.handle.net/20.500.12110/paper_09574166_v15_n19_p3023_IriarteCapaccio
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_09574166_v15_n19_p3023_IriarteCapaccio
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spelling	paper:paper_09574166_v15_n19_p3023_IriarteCapaccio2023-06-08T15:56:28Z Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones 1,3 butadiene 6 acetoxymethyl 2 (2 propyloxy) 2h pyran 3(6h) one 6 methyl 2 (2 propyloxy) 2h pyran 3(6h) one aldohexose alkadiene cyclopentadiene derivative galactose hexose ketone derivative Lewis acid pyran derivative unclassified drug addition reaction article carbon nuclear magnetic resonance catalysis cycloaddition diastereoisomer Diels Alder reaction enantiomer nuclear magnetic resonance spectroscopy nuclear Overhauser effect priority journal thin layer chromatography ultraviolet spectroscopy The thermal and Et 2O·BF 3-catalyzed Diels-Alder additions of 2,3-dimethylbutadiene and cyclopentadiene to (2S,6S)-6- acetoxymethyl-2-(2-propyloxy)-2H-pyran-3(6H)-one 1, derived from d-galactose, afforded the corresponding enantiomerically pure tetrahydrobenzopyrones resulting from the addition of the diene to the α or β face of 1. The facial and endo-exo selectivities in the formation of the adducts, and their yields, are influenced by the diene and the reaction conditions employed. In particular, low overall yields were obtained in the Lewis acid-promoted reactions. This was attributed to the presence of a Lewis base (an acetoxymethyl group) in the pyranone 1. Therefore, (2R,6S)-6-methyl-2-(2-propyloxy)-2H-pyran- 3(6H)-one 7, which possesses a C-6 methyl substituent instead of an acetoxymethyl, was prepared from l-fucose and subjected to the Et 2O·BF 3-catalyzed addition of cyclopentadiene. As expected, a good yield (74%) of the corresponding Diels-Alder product was obtained, with excellent β- and endo-diastereoselectivities. 2004 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09574166_v15_n19_p3023_IriarteCapaccio http://hdl.handle.net/20.500.12110/paper_09574166_v15_n19_p3023_IriarteCapaccio
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	1,3 butadiene 6 acetoxymethyl 2 (2 propyloxy) 2h pyran 3(6h) one 6 methyl 2 (2 propyloxy) 2h pyran 3(6h) one aldohexose alkadiene cyclopentadiene derivative galactose hexose ketone derivative Lewis acid pyran derivative unclassified drug addition reaction article carbon nuclear magnetic resonance catalysis cycloaddition diastereoisomer Diels Alder reaction enantiomer nuclear magnetic resonance spectroscopy nuclear Overhauser effect priority journal thin layer chromatography ultraviolet spectroscopy
spellingShingle	1,3 butadiene 6 acetoxymethyl 2 (2 propyloxy) 2h pyran 3(6h) one 6 methyl 2 (2 propyloxy) 2h pyran 3(6h) one aldohexose alkadiene cyclopentadiene derivative galactose hexose ketone derivative Lewis acid pyran derivative unclassified drug addition reaction article carbon nuclear magnetic resonance catalysis cycloaddition diastereoisomer Diels Alder reaction enantiomer nuclear magnetic resonance spectroscopy nuclear Overhauser effect priority journal thin layer chromatography ultraviolet spectroscopy Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones
topic_facet	1,3 butadiene 6 acetoxymethyl 2 (2 propyloxy) 2h pyran 3(6h) one 6 methyl 2 (2 propyloxy) 2h pyran 3(6h) one aldohexose alkadiene cyclopentadiene derivative galactose hexose ketone derivative Lewis acid pyran derivative unclassified drug addition reaction article carbon nuclear magnetic resonance catalysis cycloaddition diastereoisomer Diels Alder reaction enantiomer nuclear magnetic resonance spectroscopy nuclear Overhauser effect priority journal thin layer chromatography ultraviolet spectroscopy
description	The thermal and Et 2O·BF 3-catalyzed Diels-Alder additions of 2,3-dimethylbutadiene and cyclopentadiene to (2S,6S)-6- acetoxymethyl-2-(2-propyloxy)-2H-pyran-3(6H)-one 1, derived from d-galactose, afforded the corresponding enantiomerically pure tetrahydrobenzopyrones resulting from the addition of the diene to the α or β face of 1. The facial and endo-exo selectivities in the formation of the adducts, and their yields, are influenced by the diene and the reaction conditions employed. In particular, low overall yields were obtained in the Lewis acid-promoted reactions. This was attributed to the presence of a Lewis base (an acetoxymethyl group) in the pyranone 1. Therefore, (2R,6S)-6-methyl-2-(2-propyloxy)-2H-pyran- 3(6H)-one 7, which possesses a C-6 methyl substituent instead of an acetoxymethyl, was prepared from l-fucose and subjected to the Et 2O·BF 3-catalyzed addition of cyclopentadiene. As expected, a good yield (74%) of the corresponding Diels-Alder product was obtained, with excellent β- and endo-diastereoselectivities.
title	Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones
title_short	Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones
title_full	Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones
title_fullStr	Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones
title_full_unstemmed	Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones
title_sort	enantiomerically pure diels-alder cycloadducts from aldohexose-derived dihydropyranones
publishDate	2004
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09574166_v15_n19_p3023_IriarteCapaccio http://hdl.handle.net/20.500.12110/paper_09574166_v15_n19_p3023_IriarteCapaccio
_version_	1768544327488765952

Enantiomerically pure Diels-Alder cycloadducts from aldohexose-derived dihydropyranones

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