- The Baylis-Hillman reaction: a strategic tool for the synthesis of higher-carbon sugars
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The Baylis-Hillman reaction of acyclic sugar-derived aldehydes is invoked as an attractive synthetic strategy for ready access to higher-carbon sugars.
- Radha Krishna, Palakodety,Narasimha Reddy,Sreeshailam,Uday Kiran,Jagdeesh
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p. 6466 - 6470
(2008/02/12)
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- Condensation of D-mannosaldehyde derivatives with ethyl diazoacetate. An easy and stereoselective chain elongation methodology for carbohydrates: Application to new syntheses for KDO and 2-deoxy-β-KDO
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(3R and 3S) β-Hydroxy-α-diazocarbonyl compounds 4 (100%, 3:2), 9 (35%, 100:0), 14 (74%, 7:2) and 18 (100%, 100:0), prepared from 2,3,4,5,6-penta-O-acetyl-(3), penta-O-benzyl- (8), 2,3:5,6-di-O-isopropylidene-4-O-(tert-butyldimethylsilyl)- (13), and 2,3:5,6-di-O-isopropylidene-4-O-acetyl-D-mannosaldehyde (17), respectively, were acetylated, and the resulting β-3cetoxy-α-diazocarbonyl compounds treated with rhodium diacetate to give the corresponding α-enol esters, 6 (100%). 11 (35%), 16 (100%) and 20 (100%) which are potentially α-keto eaters. Molecular mechanics calculations were used in order to justify the stereoselectivity observed in the initial addition process: The problematic removal of the projecting groups from the α-enol esters is discussed. Finally, hydrazinolysis of the a-enol acetates (to quench the labile resulting α-keto ester as the corresponding and less reactive hydrazines), mild oxidation to the corresponding α-diazoesters, deprotection, and final oxidation of the diazo group with m-chloroperbenzoic acid, gave KDO in good yield. Intermediate products were used in the completely stereoselective synthesis of 2-deoxy-β-KDO, a potent inhibitor for CMP-KDO synthetase.
- Lopez-Herrera, Fidel J.,Sarabia-Garcia, Francisco
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p. 3325 - 3346
(2007/10/03)
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- TOTAL SYNTHESIS OF (+)-CASTANOSPERMINE FROM D-MANNOSE
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A total synthesis of (+)-castanospermine (2) has been achieved starting from D-mannose by a route adopting a double-cyclization process (5c-6) as the key step.
- Setoi, Hiroyuki,Takeno, Hidekazu,Hashimoto, Masashi
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p. 4617 - 4620
(2007/10/02)
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