Results 161 to 170 of about 2,875 (189)

Microwave-Assisted [3 + 2] Cycloadditions of Azomethine Ylides

Organic Letters, 2003
The microwave-assisted intramolecular [3 + 2] cycloaddition reaction of azomethine ylides to activated and nonactivated alkenes and alkynes is described. The procedure allows the synthesis of pyrrolidines and pyrrole products in good to excellent overall yields in short reaction times.
George, Bashiardes, Imad, Safir, Achmet Said, Mohamed, Francis, Barbot, Joelle, Laduranty   +4 more
openaire   +2 more sources

Reaction of Functionalized Azomethine Ylides with Olefinic Dipolarophiles

HETEROCYCLES, 2006
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Keisuke Kawashima, Akikazu Kahehi, Michihiko Noguchi   +2 more
openaire   +1 more source

The azomethine ylide strategy for β-lactam synthesis. An evaluation of alternative pathways for azomethine ylide generation

Journal of the Chemical Society, Perkin Transactions 1, 2001
Following the generation of azomethine ylide 3 from the β-lactam-based oxazolidinone 1, a series of alternative entries to this and related 1,3-dipoles have been explored. The first approach is based on the use of monocyclic azetidinones 6–12 and 14 carrying a leaving group at C(4) and an activated (acidic) proton adjacent to the ring nitrogen ...
Brown, D, Martel, SR, Wisedale, R, Charmant, JPH, Hales, NJ, Fishwick, CWG, Gallagher, TC   +6 more
openaire   +2 more sources

Recent Advances in Azomethine Ylide Chemistry

1989
Publisher Summary Azomethine ylides are planar molecules composed of one nitrogen and two terminal sp2 carbons. At most, four geometrical isomers are possible for these transient molecules. Their cycloadditions to olefin or acetylene dipolarophiles give rise to the formation of two sets of carbon-carbon bonds in a single step.
Otohiko Tsuge, Shuji Kanemasa
openaire   +1 more source

ChemInform Abstract: Benzotriazolylmethylaminosilanes: Novel Azomethine Ylide Equivalents.

ChemInform, 1995
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
A. R. KATRITZKY, J. KOEDITZ, H. LANG
openaire   +1 more source

1,7-Electrocyclisation of non-stabilised azomethine ylides

Tetrahedron Letters, 1998
Abstract Non-stablilised α,β;γ,δ-unsaturated azomethine ylides 3 were generated by the decarboxylation method from 3,3-diarylpropenals 1 and secondary amino acids 2 . 1,7-Electrocyclisation of these azomethine ylides, followed by a 1,5-hydrogen shift, gives 2,3-dihydro-1 H -2-benzazephines 4 .
Andrea Arany, Paul W. Groundwater, Miklòs Nyerges   +2 more
openaire   +1 more source

Azomethine ylide generation via the dipole cascade

Tetrahedron, 1992
Abstract A series of N-acyl 2-diazo-3-oxobutanoates, when treated with a catalytic quantity of a rhodium(II) carboxylate, were found to afford substituted pyrroles derived from an azomethine ylide intermediate. The initial reaction involves generation of the expected carbonyl ylide dipole by intramolecular cyclization of the keto carbenoid onto the ...
Albert Padwa, Dennis C. Dean, Donald L. Hertzog, William R. Nadler, Lin Zhi   +4 more
openaire   +1 more source

ChemInform Abstract: Enantioselective Cycloadditions of Azomethine Ylides

ChemInform, 2009
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Carmen Najera, Jose M. Sansano
openaire   +1 more source

Fused aziridines as sources of azomethine ylides

Chemistry of Heterocyclic Compounds, 2012
The use of fused aziridines as sources of azomethine ylides in the synthesis of polyheterocyclic compounds is examined. Features of thermo- and photolytic opening of aziridines and aspects of the stereo-, regio-, and chemoselectivity of cycloaddition and electrocyclization of azomethine ylides are discussed.
A. F. Khlebnikov, M. S. Novikov
openaire   +1 more source

Azomethine, carbonyl and thiocarbonyl ylides

2002
Abstract Simple addition of a carbene or carbenoid to a C-N double bond would be expected to result in the formation of an azomethine ylide. This is consistent with electrophilic attack of the carbene at the nitrogen atom lone pair. Formation of ylides in this manner was reviewed by Padwa and Hornbuckle in 1991.
openaire   +1 more source