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Various Alkenes (various + alkene)

Distribution by Scientific Domains
Chemistry100%
Distribution within Chemistry
General & Introductory Chemistry50%

Selected Abstracts

Cycloaddition Reaction of Epoxides with Various Alkenes under Microwave Irradiation.

CHEMINFORM, Issue 37 2003
Ghania Bentabed
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

3-Tocopherylisoxazolines by [2+3] Cycloaddition

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2004
Thomas Rosenau
Abstract New isoxazoline derivatives of ,-tocopherol (1), the main component of vitamin E, were synthesized in a facile, two-step sequence consisting of nitration followed by 1,3-dipolar cycloaddition. 5-Nitromethyl-,-tocopheryl acetate (3), obtained from the cheap ,-tocopheryl acetate (2) by direct nitration in one step, acted as the nitrile oxide precursor in the reaction with various alkenes. The facile conversion proceeded in the presence of equimolar amounts of PhNCO and catalytic amounts of triethylamine. The NMR spectra of the product isoxazolines 5,13, showing strongly temperature-dependent resonances of the 4,,-CH, 4-CH2 and the acetyl group, are discussed, and the crystal structures of model compounds containing a methyl group instead of the isoprenoid side chain are presented. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Cobalt- and Nickel-Catalyzed Regio- and Stereoselective Reductive Coupling of Alkynes, Allenes, and Alkenes with Alkenes

CHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2008
Masilamani Jeganmohan Dr.
Abstract Transition-metal-catalyzed coupling of two different CC , components through a metallacycle intermediate is a highly atom economical method to construct CC bonds in organic synthesis. The metal-catalyzed coupling of an alkene and alkyne generally gives an Alder-ene or reductive coupling product. In this article, we focus on the cobalt- and nickel-catalyzed reductive coupling of alkynes, allenes, and alkenes with alkenes. These reductive coupling reactions provide convenient methods for the synthesis of various alkenes, dienes, functionalized alkanes, lactones, lactams, and cyclic alcohols in a highly regio- and stereoselective manner. A chemselective formation of metallacyclopentene intermediate from the two different CC , components and a low-valence metal species plays a key role for the high regio- and stereoselectivity of the catalytic reaction. [source]

Enantioselective Dihydroxylation of Alkenes Catalyzed by a PEG-Bound Bi-Cinchona Alkaloid Ligand

CHINESE JOURNAL OF CHEMISTRY, Issue 1 2005
Xi-Wen Yang
Abstract The recyclable PEG-bound bi-cinchona alkaloid ligand has been successfully applied to the homogeneous catalytic asymmetric dihydroxylation of various alkenes; good yields and excellent enantioselectivities were obtained. The ligand could be easily recovered and reused for 10 times without any apparent loss of its catalyst efficiency. [source]