132377-62-9Relevant academic research and scientific papers
Synthesis and Reactions of 3-Hydroxy-2-nosyloxy Esters Produced by the Stereoselective Reduction of 2-Nosyloxy-3-keto Esters
Hoffman, Robert V.,Kim, Hwa-Ok
, p. 6759 - 6764 (2007/10/02)
The reduction of 2-nosyloxy-3-keto esters is an effective method for the preparation of 3-hydroxy-2-nosyloxy esters.The reduction is stereoselective for the syn isomer.The anti isomer can be produced as the major product by the addition of p-nitrobenzenesulfonyl peroxide to ketene bis-silyl acetal derivatives of 3-hydroxy esters.The diastereomers are separable chromatographically and can be converted stereospecifically to glycidic esters and 2-azido-3-hydroxy esters.As such they appear to have excellent potential as versatile synthetic intermediates for the synthesis of 1,2,3-trifunctional substances.
Selective Transformations of threo-2,3-Dihydroxy Esters
Fleming, Paul R.,Sharpless, K. Barry
, p. 2869 - 2875 (2007/10/02)
Two highly regio- and stereoselective transformations of threo-2,3-dihydroxy esters have been developed.In the first reaction, the α-hydroxy group is converted into a sulfonate group (tosylate or nosylate); the α-tosylates and α-nosylates are then subjected to basic conditions (K2CO3/ROH) to give erythro glycidic esters in high yield.The α-nosylates are also suitable electrophiles for azides, giving access to erythro-α-azido-β-hydroxy esters.The second reaction involves conversion of the diol esters to acetoxy bromo esters.The β-subsituent plays a key role in determining the regiochemistry since cases with β-alkyl substituents afford β-acetoxy-α-bromo esters exclusively, whereas a β-phenyl substitutent directs formation of the α-acetoxy-β-bromo ester.The acetoxy bromo esters can subsequently be converted to the threo glycidic esters (via the bromohydrin esters); selective hydrogenolysis of the bromine substituent can also be achieved.
