127762-22-5Relevant academic research and scientific papers
Synthesis of butenolides recently isolated from marine microorganisms
Karlsson, Staffan,Andersson, Fredrik,Breistein, Palle,Hedenstr?m, Erik
, p. 7878 - 7881 (2008/03/11)
The syntheses and 13C NMR analyses of four diastereomeric butenolides, two of which were recently isolated from the marine microorganisms Streptomycete B 5632 and Streptoverticillium luteoverticillatum 11014 are described. The two isolated butenolides were found to be one of the two diastereomers (4S,10R*,11R*)-4,11-dihydroxy-10-methyl-dodec-2-en-1,4-olide (RRS-1 or SSS-1) and one of the two diastereomers (4S,10S*,11R*)-4,11-dihydroxy-10-methyl-dodec-2-en-1,4-olide (SRS-1 or RSS-1). An asymmetric 1,3-dipolar cycloaddition of a thiocarbonyl ylide with a dipolarophile attached to camphorsultam and a ring-opening of an enantiomerically pure vinyloxirane by lithiated dithiane served as key steps for the construction of the three stereogenic centres. Further elaborations including ring-closing metathesis and Mitsunobu inversion furnished the four diastereomeric butenolides.
The samarium(II)-mediated intermolecular couplings of ketones and β-alkoxyacrylates: A short asymmetric synthesis of an antifungal γ-butyrolactone
Kerrigan, Nessan J.,Upadhyay, Tejas,Procter, David J.
, p. 9087 - 9090 (2007/10/03)
The samarium(II) iodide-mediated coupling of ketones with β-alkoxyacrylates gives β-hydroxy-γ-butyrolactones in moderate yield. The process has been applied to the asymmetric synthesis of an antifungal, γ-butyrolactone natural product.
Enantiomerically pure trans-3,4-disubstituted tetrahydrothiophenes from diastereoselective thiocarbonyl ylide addition to chiral α,β-unsaturated amides
Karlsson, Staffan,H?gberg, Hans-Erik
, p. 1667 - 1669 (2008/02/10)
(matrix presented). Asymmetric 1,3-dipolar cycloadditions of a sulfur-containing 1,3-dipole and α,β-unsaturated camphorsultam amides as dipolarophiles are described. The cycloaddition products, trans-3,4-disubstituted tetrahydrothiophenes, were obtained in high diastereomeric ratios (up to 90:10) and in high yields. Chromatographic removal of the minor diastereomer followed by cleavage of the chiral auxiliary furnished either the enantiomerically pure corresponding alcohol or carboxylic acid.
Functionally Substituted Vinyl Carbanions, 42: Synthesis of the Top Half of Chlorothricolide
Hirsenkorn, Rolf,Schmidt, Richard R.
, p. 883 - 899 (2007/10/02)
β-Lithiated functionally substituted acrylates 2a-c prove to be versatile building blocks for spirotetronate syntheses useful in top half syntheses of the aglycon chlorothricolide 1 of the macrolide antibiotic chlorothricin.The electrophilic-nucleophilic cyclohexanone derivatives 27-cis/trans (with relative cis or trans relationship of the carboxylate group) required in this synthesis design are obtained via a cycloaddition route from pentenone in five steps.Generation of the dilithiated species from the acrylates 2a-c affords then the corresponding spirotetronates 32a-c, which serve as versatile intermediates in top half syntheses for different strategies in chlorothricolide total syntheses.Hydroxylation in the vinylic α-position of the tetronate moiety and selective phenylselenylation provide the spirotetronates 39a-cis/trans and 41a, which meet the requirements of a top half molecule.The same is true for a different strategy, which provides the aldehydes 42b-cis/trans.The latter are then converted into the fully functionalized spirotetronates 44b-cis/trans by treatment with vinylmagnesium bromide and subsequent hydroxylation at the vinylic α-position.The investigations delineate similar convenient strategies for the syntheses of kijanolide and tetronolide, which are the aglycon portions of the structurally related macrolide antibiotics kijanimicin and tetrocarcin, respectively.
