Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars

Benzyl and 2-propyl 6-O-acetyl-3,4-dideoxy-α-D-glycero-hex-3-enopyranosid-2-uloses (2) and (3) were readily prepared by the tin(IV) chloride-promoted glycosylation of glycal (1). The enone system of (2) and (3) underwent a highly diastereoselective Michael addition of thiols (ethanethiol, propane-2-...

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Detalles Bibliográficos
Autores principales:	Uhrig, María Laura, Varela, Oscar José
Publicado:	2002
Materias:	Acetylation Benzene Carbon Derivatives Hydrogen Nuclear magnetic resonance spectroscopy Synthesis (chemical) Glycosylation Sugar enones Sugar (sucrose)
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00049425_v55_n1-2_p155_Uhrig http://hdl.handle.net/20.500.12110/paper_00049425_v55_n1-2_p155_Uhrig
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00049425_v55_n1-2_p155_Uhrig
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spelling	paper:paper_00049425_v55_n1-2_p155_Uhrig2023-06-08T14:29:45Z Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars Uhrig, María Laura Varela, Oscar José Acetylation Benzene Carbon Derivatives Hydrogen Nuclear magnetic resonance spectroscopy Synthesis (chemical) Glycosylation Sugar enones Sugar (sucrose) Benzyl and 2-propyl 6-O-acetyl-3,4-dideoxy-α-D-glycero-hex-3-enopyranosid-2-uloses (2) and (3) were readily prepared by the tin(IV) chloride-promoted glycosylation of glycal (1). The enone system of (2) and (3) underwent a highly diastereoselective Michael addition of thiols (ethanethiol, propane-2-thiol, and benzenemethanethiol) to afford the sulfur-containing hexopyranosid-2-ulose derivatives (4a-c) and (5a-c) in good yields. Sodium borohydride reduction of the carbonyl functionalities of (4b,c) and (5b) led to the corresponding 3-deoxy-4-thiohexopyranosides having the D-xylo (6b), (6c), and (8b) or the D-lyxo (7b), (7c), and (8c) configuration. Standard acetylation of these compounds gave the corresponding per-O-acetyl derivatives (10b), (10c), and (12b) and (11b), (11c), and (13b), useful for confirming all the previous configurational assignments by means of their 1H and 13C nuclear magnetic resonance spectra. Furthermore the 2-ulose (5b) proved to be a key intermediate for the synthesis of C-2 branched-chain 4-thiopyranosides, such as (16). The latter was synthesized by a good yielding ammonium acetate-catalysed Knoevenagel-type condensation of malononitrile with (5b). Fil:Uhrig, M.L. 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. 2002 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00049425_v55_n1-2_p155_Uhrig http://hdl.handle.net/20.500.12110/paper_00049425_v55_n1-2_p155_Uhrig
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Acetylation Benzene Carbon Derivatives Hydrogen Nuclear magnetic resonance spectroscopy Synthesis (chemical) Glycosylation Sugar enones Sugar (sucrose)
spellingShingle	Acetylation Benzene Carbon Derivatives Hydrogen Nuclear magnetic resonance spectroscopy Synthesis (chemical) Glycosylation Sugar enones Sugar (sucrose) Uhrig, María Laura Varela, Oscar José Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars
topic_facet	Acetylation Benzene Carbon Derivatives Hydrogen Nuclear magnetic resonance spectroscopy Synthesis (chemical) Glycosylation Sugar enones Sugar (sucrose)
description	Benzyl and 2-propyl 6-O-acetyl-3,4-dideoxy-α-D-glycero-hex-3-enopyranosid-2-uloses (2) and (3) were readily prepared by the tin(IV) chloride-promoted glycosylation of glycal (1). The enone system of (2) and (3) underwent a highly diastereoselective Michael addition of thiols (ethanethiol, propane-2-thiol, and benzenemethanethiol) to afford the sulfur-containing hexopyranosid-2-ulose derivatives (4a-c) and (5a-c) in good yields. Sodium borohydride reduction of the carbonyl functionalities of (4b,c) and (5b) led to the corresponding 3-deoxy-4-thiohexopyranosides having the D-xylo (6b), (6c), and (8b) or the D-lyxo (7b), (7c), and (8c) configuration. Standard acetylation of these compounds gave the corresponding per-O-acetyl derivatives (10b), (10c), and (12b) and (11b), (11c), and (13b), useful for confirming all the previous configurational assignments by means of their 1H and 13C nuclear magnetic resonance spectra. Furthermore the 2-ulose (5b) proved to be a key intermediate for the synthesis of C-2 branched-chain 4-thiopyranosides, such as (16). The latter was synthesized by a good yielding ammonium acetate-catalysed Knoevenagel-type condensation of malononitrile with (5b).
author	Uhrig, María Laura Varela, Oscar José
author_facet	Uhrig, María Laura Varela, Oscar José
author_sort	Uhrig, María Laura
title	Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars
title_short	Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars
title_full	Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars
title_fullStr	Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars
title_full_unstemmed	Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars
title_sort	michael addition of thiols to sugar enones. synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and c-2 branched-chain 4-thiosugars
publishDate	2002
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00049425_v55_n1-2_p155_Uhrig http://hdl.handle.net/20.500.12110/paper_00049425_v55_n1-2_p155_Uhrig
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_version_	1768546518885728256

Michael addition of thiols to sugar enones. Synthesis of 3-deoxy-4-thiohexopyranosid-2-uloses as key precursors of 3-deoxy- and C-2 branched-chain 4-thiosugars

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