- Synthesis of bioactive natural products by asymmetric syn-and anti-aldol reactions
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The use of several variants of the asymmetric aldol reaction as key steps in the syntheses of bioactive target molecules is described. Georg Thieme Verlag Stuttgart.
- Ghosh, Arun K.,Dawson, Zachary L.
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scheme or table
p. 2992 - 3002
(2010/04/02)
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- Asymmetric total synthesis of the gastroprotective microbial agent AI-77-B
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An enantioselective total synthesis of the pseudopeptide microbial agent AI-77-B, which has shown potent antiulcerogenic properties, is described. The synthesis is convergent and involves the assembly of a dihydroisocoumarin fragment and a hydroxy amino acid. The dihydroisocoumarin derivative was synthesised by means of a Diels-Alder reaction between 1-methoxy-1,3-cyclohexadiene and an alkynyl ester derivative as the dienophile. The alkynyl ester was obtained stereoselectively by two different synthetic routes: (1) A stereoselective allylation of leucinal, and (2) a titanium enolate-mediated anti-aldol reaction with trichlorobutyraldehyde, a novel homopropargylaldehyde equivalent. The stereocentres of the hydroxy amino acid moiety were generated through a titanium enolate-mediated syn-aldol reaction, Curtius rearrangement, and application of Dondoni's aldehyde homologation. Condensation of the dihydroisocoumarin and hydroxy amino acid moieties and subsequent removal of the protecting groups furnished optically active AI-77-B. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
- Ghosh, Arun K.,Bischoff, Alexander,Cappiello, John
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p. 821 - 832
(2007/10/03)
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- Stereoselective synthesis of pseudopeptide microbial agent AI-77-B.
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[structure: see text]. An efficient and highly stereoselective synthesis of the gastroprotective natural product AI-77-B is described. The stereocenters of the hydroxy amino acid moiety were generated by an ester-derived titanium-enolate-mediated syn-aldo
- Ghosh,Bischoff,Cappiello
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p. 2677 - 2680
(2007/10/03)
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