- Lipase-catalysed deacetylation of botryodiplodin acetate
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Enantioselective deacetylation of α-(±)-botryodiplodin acetate was successfully accomplished by means of lipase PS to afford (+)-botryodiplodin and α-(+)-botryodiplodin acetate with high enantiomeric excesses. Enzyme-mediated transesterification of the acetylated molecule with n-butanol, as well as its hydrolysis in several organic solvents, are also reported. The CD spectra of (+)-botryodiplodin and α-(+)-botryodiplodin acetate are also presented.
- Forzato, Cristina,Furlan, Giada,Ghelfi, Franco,Nitti, Patrizia,Pitacco, Giuliana,Roncaglia, Fabrizio,Valentin, Ennio
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p. 447 - 450
(2007/10/03)
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- Organocatalytic Michael addition, a convenient tool in total synthesis. First asymmetric synthesis of (-)-botryodiplodin
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The asymmetric Michael addition of propionaldehyde to (2E)-(3-nitro-but-2-enyloxymethyl)-benzene 8, catalyzed by the chiral diamine (S,S)-N-iPr-2,2′-bipyrrolidine, afforded, with 93% ee, a precursor 9 of (-)-botryodiplodin. The nitro functionality of 9 was converted to a ketone via a Nef reaction to give, after a few steps, the enantiomerically enriched (-)-botryodiplodin.
- Andrey, Olivier,Vidonne, Annick,Alexakis, Alexandre
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p. 7901 - 7904
(2007/10/03)
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- Synthesis of (±)- and (-)-botryodiplodin using stereoselective radical cyclizations of acyclic esters and acetals
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Three different routes for the stereoselective synthesis of botryodiplodin have been investigated. The intramolecular allylation of acetals proved to be unsatisfactory due to unstable intermediates and poor stereocontrol. Zard intramolecular radical allyl
- Nouguier, Robert,Gastaldi, Stephane,Stien, Didier,Bertrand, Michele,Villar, Felix,Andrey, Olivier,Renaud, Philippe
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p. 3005 - 3018
(2007/10/03)
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- Intramolecular radical allylation with allylic sulfones a synthesis of (±)-botryodiplodin
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Isopropenyl-5-membered-ring acetal or lactone are potential precursors of (±)-botryodiplodin (1). Several pathways, involving 5-exo-trig ring closure onto allylic sulfones, have been investigated. The iodine atom transfer methodology allowed the preparati
- Nouguier, Robert,Gastaldi, Stephane,Stien, Didier,Bertrand, Michele,Renaud, Philippe
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p. 3371 - 3374
(2007/10/03)
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- Diastereoselective radical cyclization of bromoacetals: Efficient synthesis of (±)-botryodiplodin
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A stereoselective synthesis of (±)-botryodiplodin is presented. The key reaction is a radical cyclization of a bromoacetal (Ueno-Stork reaction). The stereogenic acetal center has been used to control the stereoselectivity of the process: the difficulty in controlling the stereochemistry at C(3) of the tetrahydrofuran moiety during the cyclization step has been overcome by a double one-pot reduction procedure starting from a gem-dibromide.
- Villar, Felix,Andrey, Olivier,Renaud, Philippe
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p. 3375 - 3378
(2007/10/03)
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- Acyclic Stereoselection in the Ortho Ester Claisen Rearrangement
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The ortho ester Claisen rearrangement of trisubstituted allylic alcohols exhibits significant levels of diastereoselection. In E allylic alcohols, a 1,3-diaxial interaction develops in the chairlike transition state leading to the anti isomer, rendering the reaction syn selective by a factor of 3-5 to 1. In Z allylic alcohols, the 1,3-diaxial interaction develops in the transition state leading to the syn isomer, generating an anti:syn selectivity of 6-15 to 1. The relative stereochemistry of the syn isomer was confirmed independently by the synthesis of the mycotoxin botryodiplodin.
- Daub, G. William,Edwards, James P.,Okada, Carol R.,Allen, Jana Westran,Maxey, Claudia Tata,Wells, Matthew S.,Goldstein, Alexandra S.,Dibley, Michael J.,Wang, Clarence J.,Ostercamp, Daniel P.,Chung, Steven,Cunningham, Paula Shanklin,Berliner, Martin A.
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p. 1976 - 1985
(2007/10/03)
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- Total Synthesis of (-)- and (+)-Botryodiplodin and (+)- and (-)-Epibotryodiplodin
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the title compounds were prepared by the conjugate addition (d.e. more than 94percent) of LiMeCNCu to the chiral isoprene units (+)-(2R)- and (-)-(2S)-benzyloxy-2,5-dihydrofuran-4-carboxaldehyde (1r and 1s) followed by methyllithium-attack on the mixture
- Rehnberg, Nicola,Magnusson, Goeran
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p. 377 - 383
(2007/10/02)
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- DIASTEREOSELECTIVE CONJUGATE ADDITION OF LITHIUM METHYLCYANOCUPRATE TO THE CHIRAL ISOPRENE UNITS 2-(R)- AND (S)-BENZYLOXY-2,5-DIHYDRO-4-FURANCARBOXALDEHYDE. TOTAL SYNTHESIS OF (-)- AND (+)-BOTRYODIPLODIN AND (+)- AND (-)-EPIBOTRYODIPLODIN.
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Conjugate addition of lithium methylcyanocuprate to the title aldehydes proceeded with high diastereoselectivity (d.e. 94percent).Methyl lithium 1,2-addition, followed by Swern oxidation of the resulting alcohols, gave benzyl botryodiplodin and benzyl epi
- Rehnberg, Nicola,Frejd, Torbjoern,Magnusson, Goeran
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p. 3589 - 3592
(2007/10/02)
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- Acyclic Stereocontrol through the Dianionic Claisen Rearrangement of β-Hydroxy Esters: Synthesis of (+/-)-Botryodiplodin
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Dianionic Claisen rearrangements of (E)- and (Z)-butenyl β-hydroxy esters afford moderate stereoselection in the construction of highly functionalized acyclic systems.The reaction proceeds with remote stereocontrol and the resulting products display three contiguous chiral centers, C(α) and C(β') stereocenters being established in the rearrangement (cf. 1z -> 3b).Experiments are described which unambiguously establish that each dianionic Claisen proceeds with excellent diastereoface selectivity and moderate chair/boat selectivity .Application of this Claisen protocol to a synthesis of the mycotoxin botryodiplodin is also described (1z -> 8b).
- Kurth, Mark J.,Yu, Chan-Mo
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p. 1840 - 1845
(2007/10/02)
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- BIOSYNTHESE DE LA BOTRYODIPLODINE, MYCOTOXINE DE PENICILLIUM ROQUEFORTI: INCORPORATIONS D'ACETATE13C>, 13C>, 13C> ET D'ACIDE ORSELLINIQUE13C-CARBOXYLE13>, 13C>
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Incorporations of 13C>, 13C>, 13C> acetate and 13C, carboxyl-13C>, 13C> orsellinic acid into botryodiplodin indicate that this mycotoxin is biosynthesized by the polyketide pathway.Orsellinic acid is a precursor of botryodiplodin.A biosynthetic pathway, using orsellinic acid as precursor, is proposed.
- Renauld, F.,Moreau, S.
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p. 1823 - 1834
(2007/10/02)
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