40844-10-8Relevant academic research and scientific papers
Isomerisation of (E)-2-tetrahydrofurylidenealkanecarboxylic esters and amides into their (Z) isomers by chelation control with metallated bases or Lewis acids
Hanquet, Gilles,Salom-Roig, Xavier J.,Lemeitour, Sonia,Solladie, Guy
, p. 2112 - 2119 (2007/10/03)
2-(2-Tetrahydrofurylidene)propionates, usually obtained only in the more stable (E) configuration 1, were efficiently isomerised into their (Z) isomers 2 by use of Lewis acids or metallated bases. The (E)/(Z) isomerisation was governed by different factors (type of chelating agent, nature and steric demand of the α, β-unsaturated group). We demonstrated that judicious selection of the α, β-unsaturated group, in combination with the chelating agent, afforded yields of up to 95% with either LDA [R = N(Me)2, tBu] or MgBr2 and ZnI2 (R = OBn), and that the reaction was also influenced by 1,3-allylic strains. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Diastereodivergent synthesis of the C8-C18 precursor and C1'-C11' subunit of pamamycin 607 induced by a chiral sulfoxide group
Solladié, Guy,Salom-Roig, Xavier J.,Hanquet, Gilles
, p. 2737 - 2740 (2007/10/03)
A key step in obtaining the C8-C18 and C1'-C11' fragments of pamamycin 607, which differ by the syn- and anti-configuration of one chiral center α to the tetrahydrofuran ring, was the chelation controlled E-Z-isomerization of the substituted vinyl tetrahydrofuran intermediate 3a which has so far been obtained only in the more stable E-configuration. (C) 2000 Elsevier science Ltd.
REACTION OF DIANIONS DERIVED FROM β-KETOESTERS WITH EPOXIDES - UTILITY IN THE PREPARATION OF SYNTHETICALLY USEFUL TETRAHYDROFURANS.
Lygo, Barry,O'connor, Norval,Wilson, Peter R.
, p. 6881 - 6888 (2007/10/02)
Presented here are several examples which demonstrate that ether substituents α- or β- to an epoxide ring can be tolerated in the ring-opening reaction with β-keto ester dianions.Subsequent acid-promoted cyclisation of the γ-hydroxy β-ketoesters then leads to synthetically useful tetrahydrofurans, as demonstrated by application of this approach to the preparation of (+/-)-methyl nonactate and (+/-)-methyl 8-epi-nonactate.
STEREOSELECTIVE SYNTHESIS OF (+/-)-METHYL NONACTATE AND (+/-)-METHYL 8-epi-NONACTATE.
Lygo, Barry,O'Connor, Norval
, p. 3597 - 3600 (2007/10/02)
(+/-)-Methyl nonactate (2) and (+/-)-methyl 8epi-nonactate (3), synthetic precursors to the antibiotic nonactin have been synthesised, employing the reaction of substituted epoxides with dianions derived from β-ketoesters as the key carbon-carbon bond-for
