A samarium-promoted synthesis of (E)-nitroalkenes from 1-bromo-1-nitroalkan-2-ols in high yields and with total selectivity is reported. This reaction together with the easy and efficient preparation of the 1-bromo-1-nitroalkan-2-ols constitutes a simple and advantageous alternative toward nitroalkenes with total E-stereoselectivity. A mechanism is proposed to explain the E-stereoselectivity of the beta-elimination reaction.
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Org Lett
July 2007
Departamento de Química OrgAnica e InorgAnica, Universidad de Oviedo, Julián Clavería 8, 33071 Oviedo, Spain.
A samarium-promoted cyclopropanation of unmasked alpha,beta-unsaturated acids is described. This reaction can be carried out on (E)- or (Z)-alpha,beta-unsaturated carboxylic acids. In all cases the process is completely stereospecific and stereoselective.
View Article and Find Full Text PDFJ Org Chem
July 2007
Departamento Química Orgánica e Inorgánica, Universidad de Oviedo, JuliAn Clavería 8, 33071 Oviedo, Spain.
J Org Chem
April 2004
Department of Chemistry and Biochemistry and Walther Cancer Research Center, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, USA.
1,10-Phenanthroline reacts with aldehydes and ketones in the presence of samarium diiodide to produce 2-(1-hydroxyalkyl)-1,10-phenanthrolines. The hydroxyalkyl substituent can be functionalized in numerous ways or removed to permit further ligand variation. The carbonyl coupling reaction can also be repeated to provide 2,9-disubstituted phenanthrolines.
View Article and Find Full Text PDFOrg Lett
November 1999
Department of Chemistry, University of Notre Dame, Indiana 46556, USA.
[formula: see text] 1,10-Phenanthroline undergoes coupling with ketones promoted by samarium diiodide to produce 2-(1-hydroxyalkyl)-1,10-phenanthrolines. O-Methylation of these derivatives provides the corresponding 2-(1-methoxyalkyl)phenanthrolines. Demethoxylation with samarium diiodide then affords 2-alkylphenanthrolines.
View Article and Find Full Text PDFJ Med Chem
September 1994
Laboratory of Medicinal Chemistry, National Cancer Institute, NIH, Bethesda, Maryland 20892.
The glycon moiety of nucleosides in solution is known to exist in a rapid dynamic equilibrium between extreme northern and southern conformations as defined by the pseudorotation cycle. The concept of preparing rigid nucleoside analogues with the glycon conformation locked in one of these two extremes was tested with the synthesis of some cyclopropane-fused dideoxycarbocyclic nucleosides, similar to the well-known class of anti-HIV active dideoxynucleosides. The new compounds described here are dideoxynucleoside analogues of the fermentation product neplanocin C (6) which exhibits a typical northern geometry for its 6-oxabicyclo[3.
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