Reaction of diaryl-1,2-diones with homophthalic anhydride: efficient formation of isobenzofuranone derivatives

The reactions of homophthalic anhydride with benzils afford isobenzofuranone derivatives

Nucleophilic heterocyclic carbene as a novel catalyst for cyclopropanation of cyano acrylates

Nucleophilic heterocyclic carbenes (NHCs) have been used for the first time as catalysts in the cyclopropanation of ethyl cyanocinnamates with phenacyl bromide by Michael-initiated ring-closure (MIRC)

A facile synthesis of thiaaza- and thiadiaza-fluorene derivatives involving benzothiazole-DMAD zwitterion with arylidenemalononitriles and N-tosylimines

An efficient protocol for the one-pot synthesis of thiaazafluorene and thiadiazafluorene derivatives are described

Non-innocent probes in direct sonication: Metal assistance in oxidative radical CH functionalization

Direct sonication by means of ultrasound horns constitutes a widely used technique in chemical process technology. However, the direct contact between the metal probe and the reaction mixture does not always leave the chemical system unaffected. In this report, we study the tert-butyl hydroperoxide-mediated trifluoromethylation of heterocyclic structures, and the influence of sonication thereon. Metal leaching is observed during the process and further examined, showing that several metals can interfere significantly with the chemical reaction under study. Notably, vanadium metal was found to increase the reaction rate exceptionally well, rendering it a useful additive for this type of reactions. Ultimately, some mechanistic considerations are offered, to provide more insight into the nature of the catalytic effect of leached metals.status: publishe

NHC-catalysed annulation of enals to tethered dienones: efficient synthesis of bicyclic dienes

Homoenolates generated from α,β-unsaturated aldehydes using NHC catalysis underwent facile addition to dibenzylidene cyclohexanone to afford bicyclic cyclopentenes as single diastereomers

NHC-catalyzed annulation of enals and chalcones: further explorations on the novel synthesis of 1,3,4-trisubstituted cyclopentenes

The facile synthesis of 1,3,4-trisubstituted cyclopentenes via homoenolate annulation of enals with heterocycle substituted chalcones is described

N-Heterocyclic carbene (NHC) catalyzed annulation of enals and vinyl ketones: a novel synthesis of [2H]-pyranones

Homoenolate annulation of vinyl ketones led to the synthesis of dihydropyranones in contrast to cyclopentenes obtained by the homoenolate annulation of chalcones, another class of α,β-unsaturated ketones

Employing homoenolates generated by NHC catalysis in carbon-carbon bond-forming reactions: state of the art

Homoenolate is a reactive intermediate that possesses an anionic or nucleophilic carbon β to a carbonyl group or its synthetic equivalent. The recent discovery that homoenolates can be generated from α,β-unsaturated aldehydes via N-Heterocyclic Carbene (NHC) catalysis has led to the development of a number of new reactions. A majority of such reactions include the use of carbon-based electrophiles, such as aldehydes, imines, enones, dienones etc. resulting in the formation of a variety of annulated as well as acyclic products. The easy availability of chiral NHCs has allowed the development of very efficient enantioselective variants of these reactions also. The tolerance showed by NHCs towards magnesium and titanium based Lewis acids has been exploited in the invention of cooperative catalytic processes. This tutorial review focuses on these and other types of homoenolate reactions reported recently, and in the process, updates the previous account published in 2008 in this journal

A novel multicomponent reaction involving isoquinoline, allenoate and cyanoacrylates

Transient zwitterion generated from allenoate and isoquinoline was successfully intercepted with cyanoacrylates and arylidenemalononitriles to devise a novel multicomponent reaction under mild conditions