A Convergent Hetero-Diels-Alder Strategy for Asymmetric Access to a Lactone Containing Two Lipidic Chains
作者:Cong S. Vu、Nicolas Guisot、Stéphane Guillarme、Arnaud Martel、Gilles Dujardin、Muriel Pipelier、Didier Dubreuil、Christine Saluzzo
DOI:10.1002/ejoc.201200513
日期:2012.7
Eu(fod)3-catalyzed heterocycloaddition of chiral β-alkyl-N-vinyl-1,3-oxazolidin-2-ones with a heterodiene bearing a lipidic chain led to heterocycloadducts in high yield with excellent endo and facial selectivities. An original lipidic lactone, a potent precursor of a ceramide analog, was obtained in seven steps from the adduct in a convergent manner after appropriate functionalization.
Metal-free, direct conversion of α-amino acids into α-keto γ-amino esters for the synthesis of α,γ-peptides
作者:D. Hernández、A. Boto、D. Guzmán、E. Alvarez
DOI:10.1039/c7ob02033c
日期:——
An efficient, metal-free synthesis of unusual α-keto γ-amino esters from α-amino acids is achieved by a radical scission–oxidation–addition of silyloxy acrylates procedure, where no purification of the reaction intermediates is needed. This protocol can be applied to the selective modification of the C-terminal position in peptides to give α,γ-hybrids.
A novel Rh(II)-catalyzed transannulation of 1-tosyl-1,2,3-triazoles with silyl or alkyl enolethers has been developed, which enables the facile synthesis of substituted pyrroles in a regiocontrollable manner. Moreover, the methodology could be extended to access 3-pyrrolin-2-one derivatives with silyl ketene acetals used as the reaction partner.
Dynamic kinetic asymmetric transformation (DYKAT) of a series of 1,5-diols has been performed in the presence of Candida antarctica lipase B (CALB), Pseudomonas cepacia lipase II (PS-C II), and ruthenium catalyst 4. The resulting opticallypure 1,5-diacetates are useful synthetic intermediates, which was demonstrated by the syntheses of both an enantiopure 2,6-disubstituted piperidine and an enantiopure
Organocatalysed synthesis of isoxazolines initiated by a chemoselective oxa-Michael reaction of N-BocNHOH
作者:R. Noël、V. Gembus、V. Levacher、J.-F. Brière
DOI:10.1039/c3ob42406e
日期:——
An organocatalysed and chemoselective one-pot oxa-Michael-cyclocondensation reaction of N-BocNHOH to unsaturated α-ketoesters is reported which affords an original entry to enantioenriched 3-isoxazoline carboxylate derivatives as biorelevant heterocyclic frameworks.