- Studies towards the total synthesis of batzelladine A
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Application of a diastereoselective three-component coupling to the bicyclic core of the batzelladine alkaloids is described. The synthesis features the elaboration of glutamic acid by use of Eschenmoser sulfide contraction. An earlier approach is also included, which shows some limitations of dithiane chemistry when applied to the particular compounds required for this target.
- Elliott, Mark C.,Long, Matthew S.
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p. 2003 - 2011
(2007/10/03)
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The microbioloaical reduction of 3.A-diketones has been studied and some optically pure 3-hydroxy-4-ketones and 3,4-diols have been isolated with good yields. The chiral products of the reduction, which could not be obtained by direct action of microorganisms, were prepared by chemoenzymatic synthesis based on the microbiological reduction of a-ketothioacetals. The stereomers of non-8-ene-3,4-dials obtained by these methods were used for synthesizing the enantiomers of two pheromones: exo-fcreuzcomm and cndo-brevicomin. Eisevier,.
- Bel-Rhlid, Rachid,Renard, Michel F.,Veschambre, Henri
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p. 1011 - 1021
(2007/10/03)
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- Homolytic bond dissociation enthalpies of the acidic H - A bonds caused by proximate substituents in sets of methyl ketones, carboxylic esters, and carboxamides related to changes in ground state energies
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Equilibrium acidities in DMSO were measured for the N-H bonds in 15 carboxamides, and the homolytic bond dissociation enthalpies (BDEs) for these bonds were estimated. For the N-H bonds in five aliphatic carboxamides, the average pKHA is 25.5 a
- Bordwell,Zhang, Shizhong,Zhang, Xian-Man,Liu, Wei-Zhong
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p. 7092 - 7096
(2007/10/02)
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- Lewis acid mediated addition of 2-acyl-1,3-dithianes to α,β-unsaturated ketones: Synthesis of cyclohexenedione mono-dithioacetals
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2-Acyl-1,3-dithianes undergo Lewis acid-mediated conjugate addition to α,β-unsaturated ketones to provide 1,5-diketones which suffer base-catalyzed intramolecular aldol reaction to produce monodithioacetals of cyclohex-2-en-1,4-diones and cyclohex-3-en-1,
- Bulman Page, Philip C.,Marchington, Allan P.,Graham, Lisa J.,Harkin, Shaun A.,Wood, William W.
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p. 10369 - 10386
(2007/10/02)
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- Reactions of 2-acyl-1,3-dithianes with α,β-unsaturated ketones: simple preparation of cyclohexendione monoacetals
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2-Acyl-1,3-dithianes undergo efficient Lewis acid-catalysed addition to α,β-unsaturated ketones giving δ-diketones which suffer intramolecular aldol reaction to produce cyclohex-2-en-1,4 dione monoacetals and/or cyclohex-3-en-1,2-dione monoacetals.
- Bulman Page,Harkin,Marchington
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p. 7235 - 7236
(2007/10/02)
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- REACTIONS OF METALLATED 1,3-DITHIANES WITH CARBOXYLIC ACID DERIVATIVES
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2-Lithio-1,3-dithiane and 2-lithio-2-trimethylsilyl-1,3-dithiane react with nitriles to afford primary aminoketene dithioacetals in good yields; these compounds exhibit marked ambident nucleophilicity.Use of other carboxylic acid derivatives as electrophi
- Page, Philip C. Bulman,van Niel, Monique B.,Westwood, Donald
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p. 269 - 276
(2007/10/02)
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- MICROBIOLOGICAL SYNTHESIS OF VARIOUSLY PROTECTED L-GLYCERALDEHYDES IN HIGH OPTICAL PURITY
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Variously protected L-glyceraldehydes have been enantioselectively synthesized through a sequence involving acylation of formylanion equivalents with glycolic acid derivatives followed by baker's yeast mediated reduction of the resulting ketones.
- Guanti, Giuseppe,Banfi, Luca,Narisano, Enrica
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p. 3547 - 3550
(2007/10/02)
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- ENANTIOSELECTIVE SYNTHESIS OF α-HYDROXYTHIOACETALS BY THE BAKER'S YEAST REDUCTION OF α-KETOTHIOACETALS
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Asymmetric reduction of α-ketothioacetals was achieved by fermenting baker's yeast to afford optically pure α-hydroxythioacetals which play as equivalents of valuable α-hydroxy aldehydes.The utility of the present method was demonstrated in the stereosele
- Fujisawa, Tamotsu,Kojima, Eiji,Itoh, Toshiyuki,Sato, Toshio
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p. 1751 - 1754
(2007/10/02)
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