The natural aza sugar (+)-galactostatin (+)-1 has been prepared from d-serine by sequential installation of chiral 1C and 2C units employing thiazole-based reagents. Thus, the d-serine-derived methyl ester 3 was transformed by 2-thiazolyllithium (4) into the thiazolyl amino ketone 5 which, via syn stereoselective carbonyl reduction and thiazolyl-to-formyl conversion, gave the first key intermediate, the α-hydroxy β-amino aldehyde 10. The olefination of this compound by [(2-thiazolyl)-methylene]triphenylphosphorane (14) followed by osmium tetroxide cis dihydroxylation of the resulting alkene E-16 and cleavage of the thiazole ring produced the second key intermediate, the amino- and hydroxyl-protected 5-deoxy-5-amino-d-galactose 20. The removal of all protecting groups of this compound afforded the target aza sugar (+)-1 in 17.3% overall yield from 3. © 1995, American Chemical Society. All rights reserved.

Total Synthesis of (+)-Galactostatin. An Illustration of the Utility of the Thiazole-Aldehyde Synthesis

DONDONI, Alessandro;PERRONE, Daniela
1995

Abstract

The natural aza sugar (+)-galactostatin (+)-1 has been prepared from d-serine by sequential installation of chiral 1C and 2C units employing thiazole-based reagents. Thus, the d-serine-derived methyl ester 3 was transformed by 2-thiazolyllithium (4) into the thiazolyl amino ketone 5 which, via syn stereoselective carbonyl reduction and thiazolyl-to-formyl conversion, gave the first key intermediate, the α-hydroxy β-amino aldehyde 10. The olefination of this compound by [(2-thiazolyl)-methylene]triphenylphosphorane (14) followed by osmium tetroxide cis dihydroxylation of the resulting alkene E-16 and cleavage of the thiazole ring produced the second key intermediate, the amino- and hydroxyl-protected 5-deoxy-5-amino-d-galactose 20. The removal of all protecting groups of this compound afforded the target aza sugar (+)-1 in 17.3% overall yield from 3. © 1995, American Chemical Society. All rights reserved.
1995
Dondoni, Alessandro; Perrone, Daniela
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1201473
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