170238-76-3Relevant academic research and scientific papers
Synthetic studies toward potent cytotoxic agent amphidinolide B : Synthesis of the entire C14-C26 moiety of the top half
Chakraborty, Tushar K.,Thippeswamy, Devasamudram,Suresh, Vayalakkada R.,Jayaprakash, Sarva
, p. 563 - 564 (1997)
Regioselective hydroboration of a 4-methyl-2-alkene, oxidation of the resulting mixture of isomeric alcohols, and finally diastereoselective reduction of the ketone are the key steps in the stereoselective synthesis of C19-C26 fragment of amphidinolide B
Pigments of Fungi. LIX - Synthesis of (1S,3S)- and (1R,3R)-austrocortilutein and (1S,3S)-austrocortirubin from citramalic acid
Gill, Melvyn,Harte, Michael F.,Ten, Abilio
, p. 245 - 256 (2007/10/03)
The naturally occurring tetrahydroanthraquinone (1S,3S)-austrocortilutein (1) is synthesized for the first time in enantiomerically pure form by Diels-Alder cycloaddition between the functionalized butadiene derivative (8) and the chiral 1,3-dihydroxy-1,2,3,4-tetrahydro-5,8-naphthoquinone (9), the latter being derived from (R)-citramalic acid (3). The natural products (1S,3S)-austrocortirubin (2) and (1R,3R)-austrocortilutein (5) were also prepared for the first time by using the same strategy. CSIRO 2000.
Enantioselective hydrolysis of functionalized 2,2-disubstituted oxiranes with bacterial epoxide hydrolases
Steinreiber, Andreas,Osprian, Ingrid,Mayer, Sandra F.,Orru, Romano V. A.,Faber, Kurt
, p. 3703 - 3711 (2007/10/03)
The biohydrolysis of 2,2-disubstituted oxiranes bearing various oxygen functional groups was investigated using the epoxide hydrolase activity of 11 bacterial strains. The results show that the activity and the selectivity strongly depend on the substrate structure and the biocatalyst. Whereas substrates possessing free hydroxyl groups were not transformed, their analogs, protected as ethers, were well accepted. This allowed the convenient modulation of the enantioselectivity by proper choice of the ether group according to size and polarity. It was found that the distance of the ether-oxygen to the stereogenic quaternary carbon center of the oxirane ring had a profound influence on the enantioselectivity, and several oxiranes were resolved with good to excellent selectivities. The enantiomerically enriched epoxides and vicinal diols thus obtained contain a useful 'synthetic handle' in their side chain, which allows their use as building blocks in asymmetric synthesis.
Enantioselective Synthesis of 2-Methyl-2-hydroxy-γ-butyrolactone and Its Application in the Asymmetric Synthesis of Frontalin and Mevalonolactone
Davis, Franklin A.,Reddy, G. Venkat,Chen, Bang-Chi,Kumar, Anil,Haque, M. Serajul
, p. 6148 - 6153 (2007/10/03)
The asymmetric hydroxylation of the enolates of fully substituted acyclic ester 8 and lactone 10 with (camphorylsulfonyl)oxaziridines 1a - c was studied.The stereoselectivities of the tertiary α-hydroxy carbonyl products were highly dependent on the enolate structure, the oxidizing reagents, and the reaction conditions.While high diastereoselectivity (up to 94percent) was obtained for enolates of fully substituted menthol ester 8 with substoichiometric amounts of oxaziridine 1a, the yields were unsatisfactory.On the other hand, the enantioselective α-hydroxylation of the sodium enolate of 2-methyl-γ-butyrolactone (10) with oxaziridine (1c) afforded α-hydroxy lactone 11a in 70percent yield and 84percent ee.The enantiomeric excess was improved to >93percent ee by crystallization of the corresponding benzoyl ester 11c.The utility of both enantiomers of 11c were demonstrated in the formal asymmetric syntheses of the pheromone, (1S,5R)-(-)-frontalin (13) and in the asymmetric synthesis of (R)-(-)-mevalonolactone (20).
