Applications of Cyclic Sulfates of vic-Diols: Synthesis of Episulfides, Olefins, and Thio Sugars
摘要:
A new efficient and expeditious one-pot synthesis of thiiranes and olefins from cyclic sulfates of vic-diols is described. Opening of cyclic sulfates with potassium thioacetate or potassium thiocyanate followed by treatment with sodium methoxide led to episulfides. Olefins were obtained when potassium selenocyanate was used as nucleophile, and the obtained monoesters were treated with sodium borohydride. This method was applied to acyclic polyols derived from chiral glycerine, 1,2-isopropylidenehexofuranoses with different subtituents at C-3, and dimethyl acetals derived from pentoses and hexoses. The methodology is highly versatile, and its applicability has been demonstrated by the synthesis of different 4- and 5-thiosugars by opening of the thiirane ring with sodium acetate or lithium aluminum hydride. Reduction with lithium aluminum hydride of the thiocyanate sulfate potassium salt obtained by the opening of cyclic sulfate with KSCN allowed the direct synthesis of 5-deoxy-4-thio- and 6-deoxy-5-thiosugars. Cyclic thiosugars with the sulfur atom in the ring are obtained by acidic hydrolysis of the 5-thiol derivatives of 1,2-O-isopropylidenehexofuranoses and 4-thiopentose dimethyl acetals. Using this method, an efficient synthesis of 5-thio-L-fucose as well as the synthesis of 2,5-dideoxy-4-thiofuranose is described.
Cyclicsulfates of vic-diols are transformed in one-pot into sugar episulfides by treatment with potassium thioacetate or thiourea followed by reaction with sodium methoxide; reaction of these cyclicsulfates with potassium selenocyanate followed by treatment with sodium borohydride allows the synthesis of sugar olefins.
Applications of Cyclic Sulfates of <i>vic</i>-Diols: Synthesis of Episulfides, Olefins, and Thio Sugars
作者:Francisco G. Calvo-Flores、Pilar García-Mendoza、Fernando Hernández-Mateo、Joaquín Isac-García、Francisco Santoyo-González
DOI:10.1021/jo962066b
日期:1997.6.13
A new efficient and expeditious one-pot synthesis of thiiranes and olefins from cyclic sulfates of vic-diols is described. Opening of cyclic sulfates with potassium thioacetate or potassium thiocyanate followed by treatment with sodium methoxide led to episulfides. Olefins were obtained when potassium selenocyanate was used as nucleophile, and the obtained monoesters were treated with sodium borohydride. This method was applied to acyclic polyols derived from chiral glycerine, 1,2-isopropylidenehexofuranoses with different subtituents at C-3, and dimethyl acetals derived from pentoses and hexoses. The methodology is highly versatile, and its applicability has been demonstrated by the synthesis of different 4- and 5-thiosugars by opening of the thiirane ring with sodium acetate or lithium aluminum hydride. Reduction with lithium aluminum hydride of the thiocyanate sulfate potassium salt obtained by the opening of cyclic sulfate with KSCN allowed the direct synthesis of 5-deoxy-4-thio- and 6-deoxy-5-thiosugars. Cyclic thiosugars with the sulfur atom in the ring are obtained by acidic hydrolysis of the 5-thiol derivatives of 1,2-O-isopropylidenehexofuranoses and 4-thiopentose dimethyl acetals. Using this method, an efficient synthesis of 5-thio-L-fucose as well as the synthesis of 2,5-dideoxy-4-thiofuranose is described.
An Efficient Synthesis of <scp>d</scp>-<i>e</i><i>rythro</i>- and <scp>d</scp>-<i>t</i><i>hreo</i>-Sphingosine from <scp>d</scp>-Glucose: Olefin Cross-Metathesis Approach
作者:Vinod D. Chaudhari、K. S. Ajish Kumar、Dilip D. Dhavale
DOI:10.1021/ol052320z
日期:2005.12.1
[reaction: see text] The D-erythro- and D-threo-sphingosine were synthesized via E-selective olefin cross-metathesis using a D-glucose-derived building block and long-chain terminal alkene.