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-...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Uhrig, M.L., Varela, O.
Formato: JOUR
Materias:
Acetylation
Benzene
Carbon
Derivatives
Hydrogen
Nuclear magnetic resonance spectroscopy
Synthesis (chemical)
Glycosylation
Sugar enones
Sugar (sucrose)
Acceso en línea: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 todo:paper_00049425_v55_n1-2_p155_Uhrig
record_format dspace
spelling todo:paper_00049425_v55_n1-2_p155_Uhrig2023-10-03T14:03:11Z 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, M.L. Varela, O. 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. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar 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, M.L.
Varela, O.
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).
format JOUR
author Uhrig, M.L.
Varela, O.
author_facet Uhrig, M.L.
Varela, O.
author_sort Uhrig, M.L.
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
url http://hdl.handle.net/20.500.12110/paper_00049425_v55_n1-2_p155_Uhrig
work_keys_str_mv AT uhrigml michaeladditionofthiolstosugarenonessynthesisof3deoxy4thiohexopyranosid2ulosesaskeyprecursorsof3deoxyandc2branchedchain4thiosugars
AT varelao michaeladditionofthiolstosugarenonessynthesisof3deoxy4thiohexopyranosid2ulosesaskeyprecursorsof3deoxyandc2branchedchain4thiosugars
_version_ 1807314879468535808

Ejemplares similares