K. C. Sheela

1,3-Dipolar cycloaddition reactions of nitrile-N-oxides with o-benzoquinones

Abstract Di- and tri-substituted o-benzoquinones on reaction with nitrile N-oxides afforded novel mono spirodioxazole derivatives. The reaction of monosubstituted o-benzoquinones with stable nitrile oxides resulted in the formation of bis adducts.

Novel 1,3-dipolar cycloaddition reaction of carbonyl ylide with o-quinones

Abstract 1,3-Dipolar cycloaddition reaction of carbonyl ylide with o -quinones afforded novel highly oxygenated spirocyclic compounds.

A novel 3-component reaction of sarcosine and 1,2-diones

Abstract Facile multicomponent reactions involving sarcosine and 1,2-diones such as isatin, acenaphthenequinone and cyclobutene-1,2-dione yielding novel spiropyrrolidine derivatives are described.

1,3-dipolar cycloaddition reactions of carbonyl ylides with 1,2-diones: synthesis of novel spiro oxabicycles

1,3-Dipolar cycloaddition reaction of carbonyl ylides with various o-quinones afforded highly oxygenated spiro oxabicycles.

DIELS-ALDER REACTIONS OF A 6-ARENYL FULVENE WITH DIENES AND DIENOPHILES AND RELATED CHEMISTRY

Abstract 6-(2-Phenyl ethenyl) fulvene has been shown to participate both as diene and dienophile in Diels-Alder reactions and a facile photochemical transformation of the resulting bicyclo[2.2.2]-octenediones leading to extensively conjugated benzofulvenes has been accomplished.

Dipolar cycloaddition of carbonyl ylides with [60]fullerene: formation of novel heterocycle fused fullerene derivatives

Carbonyl ylides generated by Padwa protocol add to [60]fullerene affording novel heterocycle fused fullerene derivatives in moderate yields.

Cycloaddition reactions of carbonyl ylides to [60] fullerene: Synthesis of novel C60 derivatives☆

Abstract 1,3-Dipolar cycloaddition reactions of carbonyl ylides with [60] fullerene afforded novel cycloadducts.

1,3-DIPOLAR CYCLOADDITION REACTIONS OF O-BENZOQUINONES : AN OVERVIEW

The dipolar cycloaddition reactions of o-benzoquinones exhibiting different reactivity profiles with different dipoles are described. With diazomethane, the corresponding indazole is formed by the addition to C=C bond, while with mesoionic compounds, novel heterocyclic compounds are obtained. Depending on the nature of the substituents on the substrates, benzonitrile oxides add to both C=C and C=O of o-quinones. Carbonyl ylides afforded highly oxygenated spirocyclic compounds.

Novel cycloaddition reactions ofo-benzoquinones and related chemistry

Abstracto-Benzoquinone is a unique conjugated 1,2-dione that can exhibit diverse cycloaddition modes, participating either as carbodiene, heterodiene, dienophile or heterodienophile. With electron-rich dienes, benzodioxins are formed in excellent yields. Pentafulvenes including 6-vinylfulvenes normally give rise to bicyclo [2.2.2] adducts. Exceptions are observed with cycloalkylfulvenes where the fulvenes undergo rearrangement to cyclopentadiene derivatives prior to cycloaddition, resulting in benzodioxins.o-Benzoquinones participate as dipolarophiles on treatment with nitrile oxides and carbonyl ylides yielding highly oxygenated novel spiro compounds. Triphenylphosphine catalyzed addition of DMAD too-benzoquinones afforded another class of novel spirolactones. The bicyclo [2.2.] octene diones derived fromo-benzoquinones undergo a number of synthetically useful transformations.