An efficient method to rapidly synthesize 3-deoxy-d-manno-2-octulosonic acid (Kdo) and its derivatives in large scale has been developed. Starting from d-mannose, the di-O-isopropylidene derivative of Kdo ethyl ester was prepared in three steps on a scale of more than 40 g in one batch in an overall yield of 75–80% without any intermediate purification. Kdo, Kdo glycal, and 2-acetylated Kdo ester were
Syntheses of 2-Keto-3-deoxy-<scp>D</scp>-xylonate and 2-Keto-3-deoxy-<scp>L</scp>-arabinonate as Stereochemical Probes for Demonstrating the Metabolic Promiscuity of<i>Sulfolobus solfataricus</i>Towards<scp>D</scp>-Xylose and<scp>L</scp>-Arabinose
作者:Robert M. Archer、Sylvain F. Royer、William Mahy、Caroline L. Winn、Michael J. Danson、Steven D. Bull
DOI:10.1002/chem.201203489
日期:2013.2.18
conate aldolase from the archaeon Sulfolobus solfataricus demonstrates good activity for catalysis of the retro‐aldol cleavage of both these enantiomers to afford pyruvate and glycolaldehyde. The stereochemicalpromiscuity of this aldolase towards these enantiomeric aldol substrates confirms that this organism employs a metabolically promiscuous pathway to catabolise the C5‐sugars D‐xylose and L‐arabinose
Base-Catalyzed Direct Aldolization of α-Alkyl-α-Hydroxy Trialkyl Phosphonoacetates
作者:Michael T. Corbett、Daisuke Uraguchi、Takashi Ooi、Jeffrey S. Johnson
DOI:10.1002/anie.201200559
日期:2012.5.7
Pass the P: Catalytic direct aldol addition of α‐hydroxy trialkyl phosphonacetates to aldehydes affords α‐hydroxy‐β‐phosphonyloxy ester products (see scheme). The fully substituted glycolate enolate intermediate is generated in situ under mild conditions by a [1,2] phosphonate–phosphate rearrangement. High enantioselectivity and dramatic enhancement of reaction diastereocontrol is realized by the application
通过 P : α-羟基三烷基膦酸酯与醛的催化直接醛醇加成得到 α-羟基-β-膦酰氧基酯产物(见方案)。完全取代的乙醇酸烯醇酯中间体是在温和条件下通过 [1,2] 膦酸-磷酸重排原位生成的。手性亚氨基正膦催化剂的应用实现了高对映选择性和反应非对映控制的显着增强。