136599-33-2Relevant academic research and scientific papers
Asymmetric intramolecular Pd(II)-catalysed amidocarbonylation of unsaturated amino alcohols
Koos, Peter,Spanik, Ivan,Gracza, Tibor
body text, p. 2720 - 2723 (2010/04/24)
The first example of an asymmetric carbonylative bicyclisation of racemic N-protected 1-amino-pent-4-ene-3-ols (±)-1 catalysed by palladium(II) with chiral bis(oxazoline) ligands was investigated. The kinetic resolution of (±)-1 in the presence of chiral
Microbial Baeyer-Villiger oxidation applied to the synthesis of the N-protected (1R,5R)-Geisman-Waiss lactone
Luna, Amparo,Gutierrez, Maria-Concepcion,Furstoss, Roland,Alphand, Veronique
, p. 2521 - 2524 (2007/10/03)
Using whole cell Baeyer-Villiger biooxidation as a key step and depending on the choice of the biocatalyst {E. coli TOP10[pQR239] or Acinetobacter TD63}, the synthesis of nearly enantiopure N-protected (1R,5R)-(-)-Geisman-Waiss lactone (92% ee) or its (1R
A dirhodium(II)-carbenoid route to (-)- and (+)-Geissman-Waiss lactone: Synthesis of (1R,7R,8R)-(-)-turneforcidine
Wee
, p. 8513 - 8517 (2007/10/03)
(-)- and (+)-Geissman-Waiss lactone, 4b, was efficiently prepared via the intramolecular C-H insertion reaction of the chiral nonracemic diazoacetates (-)-5a and (+)-5b catalyzed by dirhodium(II) tetrakis[methyl (5R and 5S)-3-phenylpropanoyl-2-imidazolidinone-5-carboxylate]. The cyclization was found to proceed with excellent regioselectivity and cis-diastereoselectivity. The bicyclic lactone (-)-4b was successfully used in the synthesis of the necine base, (-)-turneforcidine 2.
A facile synthesis of (-)- and (+)-Geissman-Waiss lactone via intramolecular Rh(II)-carbenoid mediated C-H insertion reaction: Synthesis of (1R,7R,8R)-turneforcidine
Wee
, p. 9025 - 9029 (2007/10/03)
The intramolecular C-H insertion reaction in chiral non-racemic diazoacetates (-)-6 and (+)-8 catalyzed by chiral Rh2(MPPIM)4 proceeded efficiently, with excellent regioselectivity and cis-diastereoselectivity, to give (-)- and (+)-G
Regioselective synthesis of nitrones by decarboxylative oxidation of N- alkyl-α-amino acids and application to the synthesis of 1-azabicyclic alkaloids
Ohtake, Hiroaki,Imada, Yasushi,Murahashi, Shun-Ichi
, p. 2737 - 2754 (2007/10/03)
Tungstate-catalyzed oxidation of N-alkyl-2a-amino acids with 30% H2O2 solution under phase-transfer conditions gives nitrones regioselectively in good yields: Using this method, stereodivergent synthesis of (R)- and (S)-4- (t-butyldimethylsilyloxy)-1-pyrroline N-oxides ((R)-17a and (S)-17a) was achieved. In addition, (R)- and (S)-3-(t-butyldimethylsilyloxy)-1-pyrroline N-oxides ((R)-45 and (S)-45) were prepared by catalytic oxidation of the corresponding chiral pyrrolidines in a regioselective manner. These chiral cyclic nitrones, 17 and 45 are versatile intermediates for the synthesis of optically active nitrogen heterocycles, since stereoselective additions of carbon nucleophiles to these chiral nitrones can be readily performed. Typically, ZnI2-mediated addition of ketene t-butyldimethylsilyi methyl acetal (29a): to (R)-17a gave the' cis-adduct, methyl (2R,4R)-[1,4-bis(t- butyldimethylsilyloxy)pyrrolidin-2-yl]acetate (cis-30). In contrast, the addition of lithium acetylides 34 to the nitrone (R)-17a gave the trans- adducts, (2S,4R)-2-(1-alkynyl)-4-(t-butyldimethylsilyloxy)-1- hydroxypyrrolidines trans-35. These adducts are useful intermediates for syntheses of the nitrogen heterocycles (3R,5R)-1-aza-3- hydroxybicyclo[3.3.0]octane (37) and (6R,8R)-1-aza-8- hydroxybicyclo[4.30]nonane (38), respectively. The ZnI2-mediated addition of ketene silyl acetal 29a to the nitrone (R)-45 gave methyl (2S, 3R)-[1,3- bis(t-butyldimethylsilyloxy)pyrrolidin-2-yl]acetate (trans-50a), which was used for asymmetric synthesis of the Geissman-Waiss lactone ((-)-49).
Synthesis of (R)- and (S)-3-(tert-butyldimethylsilyloxy)-1-pyrroline N- oxides - Chiral nitrones for synthesis of biologically active pyrrolidine derivative, Geissman-Waiss lactone
Murahashi, Shun-Ichi,Ohtake, Hiroaki,Imada, Yasushi
, p. 2765 - 2766 (2007/10/03)
Tungstate-catalyzed oxidation of O-tert-butyldimethylsilyl (O-TBDMS) protected (R)-3-hydroxypyrrolidine ((R)2), derived from trans-4-hydroxy-L- proline, gave O-TBDMS protected (R)-3-hydroxy-1-pyrroline N-oxide ((R)1), which is a new chiral precursor for the synthesis of Geissman-Waiss lactone. The enantiomeric nitrone (S)-1 was also prepared by the oxidation of (S)-2 derived from L-malic acid.
Synthesis of (+/-) - oxohexahydrofuro[3,2-b]pyrroles (pyrrolidine-trans-lactones) via a reduction - Alkylation protocol
Macdonald, Simon J.F.,Montana, John G.,Buckley, Doreen M.,Dowle, Michael D.
, p. 1378 - 1380 (2007/10/03)
A synthesis of pyrrolidine-trans-lactones is described commencing from 1-(benzyloxycarbonyl)-3-oxo-2-pyrrolidineacetic acid ethyl ester. cis-Reduction of the oxo-pyrrolidine followed by hydroxyl inversion with benzoic acid in a Mitsunobu reaction gave the trans-benzoate ester which was converted into its corresponding silyl ether. After allylation α to ethyl ester, silyl deprotection, saponification and trans-lactonisation gave pyrrolidine-trans-lactones. Stereoselective allylation of trans-1-(benzyloxycarbonyl)- 3-hydroxy-2-pyrrolidine-acetic acid ethyl ester is feasible to give predominantly the desired diastereomer.
Homoproline homologation by enolate Claisen rearrangement or direct allylation: Syntheses of (-)-trachelanthamidine, (-)-isoretronecanol and (±)-turneforcidine
Knight, David W.,Share, Andrew C.,Gallagher, Peter T.
, p. 2089 - 2097 (2007/10/03)
The pyrrolizidine precursors 13 and 14 are obtained both by enolate Clalsen rearrangement of the homoproline allyl ester 12 and by direct allylation of N-protected homoproline ethyl ester 15. In both cases, the reactions show poor levels of stereoselectivity. Reduction gives the corresponding alcohols 20a and 21 a which are separated and subsequently elaborated to (-)-trachelanthamidine 24 and (-)-isoretronecanol 25 respectively via reductive alkene cleavage, mesylation and spontaneous cyclisation following N-deprotection. The chiral integrity of the original proline-derived asymmetric centre is preserved throughout. A similar enolate allylation gives, with high stereoselectivity, the homologue 34 of the Geissman-Waiss lactone 32, which is similarly transformed into (±)-turneforcidine 31.
Cycloaddition Reaction of Cyclic Enecarbamates and Enamides With Ketenes. A Short and Efficient Synthesis of the Geissman-Waiss Lactone.
Faria, Antonio R. de,Matos, Carlos Roberto R.,Correia, Carlos Roque D.
, p. 27 - 30 (2007/10/02)
The synthesis of several 2-aza-bicycloheptan-6-ones has been achieved in a regiospecific manner through a cycloaddition reaction between five-membered cyclic enecarbamates and enamides and free ketenes.The synthetic potential of this new meth
The Shortest Synthesis of Optically Active Geissman-Waiss Lactone, A Key Synthetic Intermediate for Necine Bases
Takahata, Hiroki,Banba, Yasunori,Momose, Takefumi
, p. 445 - 448 (2007/10/02)
A short synthesis of (+)-(1R,5R)-2-oxa-6-azabicyclooctan-3-one (the Geissman-Waiss lactone, 1) by palladium (II)-catalyzed intramolecular aminocarbonylation of (R)-N-benzyloxycarbonyl-3-hydroxy-4-pentenylamine (4) available from the Katsuki-Sharple
