113531-94-5Relevant academic research and scientific papers
A combined experimental and computational strategy in the assignment of absolute configurations of 4-methyl-5-oxo-tetrahydrofuran-3-carboxylic acids and their esters
Forzato, Cristina,Furlan, Giada,Nitti, Patrizia,Pitacco, Giuliana,Marchesan, Domenico,Coriani, Sonia,Valentin, Ennio
, p. 3011 - 3023 (2007/10/03)
Enantiopure cis- and trans-4-methylparaconic acids and their alkyl esters were synthesized by a procedure involving the kinetic enzymatic resolution of diastereomeric lactonic esters. Thus, ethyl cis- and trans-4-methyl-5-oxo- tetrahydrofuran-3-carboxylates were isolated, at high conversion values, with 99% ee from the hydrolyses with HLAP and α-CT, respectively. The corresponding enantiopure cis- and trans-lactonic acids were also obtained. The absolute configurations of the products were assigned by chemical correlation, by analysis of their circular dichroism spectra and by electronic structure calculations. All three methodologies lead to the same assignment for the species considered, another example of successful interplay between experiment and theory.
Organocatalytic Michael addition, a convenient tool in total synthesis. First asymmetric synthesis of (-)-botryodiplodin
Andrey, Olivier,Vidonne, Annick,Alexakis, Alexandre
, p. 7901 - 7904 (2007/10/03)
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.
Synthesis of (±)- and (-)-botryodiplodin using stereoselective radical cyclizations of acyclic esters and acetals
Nouguier, Robert,Gastaldi, Stephane,Stien, Didier,Bertrand, Michele,Villar, Felix,Andrey, Olivier,Renaud, Philippe
, p. 3005 - 3018 (2007/10/03)
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
Intramolecular radical allylation with allylic sulfones a synthesis of (±)-botryodiplodin
Nouguier, Robert,Gastaldi, Stephane,Stien, Didier,Bertrand, Michele,Renaud, Philippe
, p. 3371 - 3374 (2007/10/03)
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
Diastereoselective radical cyclization of bromoacetals: Efficient synthesis of (±)-botryodiplodin
Villar, Felix,Andrey, Olivier,Renaud, Philippe
, p. 3375 - 3378 (2007/10/03)
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.
Acyclic Stereoselection in the Ortho Ester Claisen Rearrangement
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.
, p. 1976 - 1985 (2007/10/03)
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.
Total Synthesis of (-)- and (+)-Botryodiplodin and (+)- and (-)-Epibotryodiplodin
Rehnberg, Nicola,Magnusson, Goeran
, p. 377 - 383 (2007/10/02)
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
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.
Rehnberg, Nicola,Frejd, Torbjoern,Magnusson, Goeran
, p. 3589 - 3592 (2007/10/02)
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
Acyclic Stereocontrol through the Dianionic Claisen Rearrangement of β-Hydroxy Esters: Synthesis of (+/-)-Botryodiplodin
Kurth, Mark J.,Yu, Chan-Mo
, p. 1840 - 1845 (2007/10/02)
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).
