Sinu C R

• Ph D
• Researcher at University of Southern Mississippi

Selective monofunctionalization of substrates with distant, yet equally reactive functional groups is difficult to achieve, as it requires the second functional group to selectively modulate its reactivity once the first functional group has reacted. We now show that mechanically interlocked catalytic rings can effectively regulate the reactivity o...

It's good to talk: Distant ends in rotaxanes can talk to each other in a reaction-history-dependent manner with the help of a catalytic ring, which shuttles freely between the ends. With this kinetically controlled information transfer mechanism, one end knows whether the other end has reacted, and if yes, with what reagent. The end receiving this...

Selective catalysis at the molecular level represents a cornerstone of chemical synthesis. However, it still remains an open question how to elevate tunable catalysis to larger length scales to functionalize whole polymer chains in a selective manner. We now report a hydrazone-linked tetrahedron with wide openings, which acts as a catalyst to size-...

Molecular crane arms deliver nitronium ions to specific locations of concave, polyaromatic systems in a stereoselective manner. In their Communication (DOI: 10.1002/anie.201811517), S. T. Schneebeli and co‐workers now describe how the first enantioselective aromatic nitration reactions have been achieved with the help of such crane arms. These find...

Molekulare Kranausleger bringen in stereoselektiver Weise Nitroniumionen zu spezifischen Stellen konkaver polyaromatischer Systeme. S. T. Schneebeli und Mitarbeiter beschreiben in ihrer Zuschrift (DOI: 10.1002/ange.201811517), wie die ersten enantioselektiven Nitrierungsreaktionen mithilfe solcher Kranausleger erreicht wurden. Die Ergebnisse stelle...

Enantioselective electrophilic aromatic nitration methodology is needed to advance chirality‐assisted synthesis (CAS). We now report an enantioselective aromatic nitration strategy operating with chiral diester auxiliaries, which provides an enantioselective synthesis of a C3v‐symmetric tribenzotriquinacene (TBTQ). These axially‐chiral structures a...

Enantioselective electrophilic aromatic nitration methodology is needed to advance chirality‐assisted synthesis (CAS). Reported here is an enantioselective aromatic nitration strategy operating with chiral diester auxiliaries, and it provides an enantioselective synthesis of a C3v‐symmetric tribenzotriquinacene (TBTQ). These axially‐chiral structur...

Crystal-packing forces can have a significant impact on the relative stabilities of different molecules and their conformations. The magnitude of such effects is, however, not yet well understood. Herein we show, that crystal packing can completely overrule the relative stabilities of different stereoisomers in solution. Heating of atropoisomers (i...

Crystal-packing forces can have a significant impact on the relative stabilities of different molecules and their conformations. The magnitude of such effects is, however, not yet well understood. Herein we show, that crystal packing can completely overrule the relative stabilities of different stereoisomers in solution. Heating of atropoisomers (i...

Annulation reaction of arylidene chromanones, thiochromanones, and tetralones with α,β-unsaturated aldehydes allow the synthesis of a wide variety of tricyclic pentenes.

An N-heterocyclic carbene (NHC)-mediated homoenolate reaction strategy for the efficient synthesis of a wide variety of tricyclic pentenes with potential biological activity is reported.

Tricyclic benzopyrans are medicinally important biologically active compounds. Synthesis of a series of tricyclic benzopyrans derivatives via N-Heterocyclic carbene (NHC) catalyzed annulation of enals to α-methylidenetetralones/chromanones is described. This reaction afforded the benzopyrans in high yield with aromatic as well as aliphatic enals.

A nucleophilic heterocyclic carbene-mediated intramolecular homoenolate reaction strategy for the efficient synthesis of cyclopentene-fused macrocycles is reported.

A simple NHC-catalyst promotes the reaction of enals with dienones to give unexpected cyclopentene derivatives (III).

An unexpected transformation of 1,6-diarylhexa-1,5-diene-3,4-diones (cinnamils) to 2,3,8-triaryl vinyl fulvenes via N-Heterocyclic Carbene (NHC) catalysis is reported. Mechanistic as well as synthetic novelty is the hallmark of this reaction.

A nucleophilic heterocyclic carbene mediated intramolecular homoenolate reaction strategy for the efficient synthesis of 4-alkyl substituted coumarins is described.

Transient zwitterions generated from dimethyl allenedicarboxylate and isoquinoline were successfully intercepted with 2-oxo-1H-indol-3-ylidenes to result in a facile multicomponent reaction under mild conditions.

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

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.

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 react...

An unexpected transformation of 2H-chromene-3-carboxaldehydes to coumarin derivatives, mediated by NHC, is reported.

The presented quinone—nitrone reactions are considered as a special case among quinone-1,3-dipole cycloaddition reactions.

A facile NHC-mediated reaction of aromatic aldehydes with carbon dioxide leading to carboxylic acids is described. The present protocol is mechanistically important, and it can serve as a tool for the sequestration of carbon dioxide.

ChemInform 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.

magnified image 1,3‐Dipolar cycloaddition reaction involving nitrones and benzoquinones resulting in the formation of benzisoxazolidene is described. As the nitrone is selectively added to carbon–carbon double bond of the benzoquinone, the quinone‐nitrone reaction is considered as a special case among quinone‐1,3‐dipole cycloaddition reactions. Mol...

Homoenolate generated from alpha,beta-unsaturated aldehydes by NHC catalysis underwent facile addition to conjugated sulfonimines, generated in situ, and subsequent methanolysis to afford protected GABA derivatives stereoselectively and in high yields, thus constituting a novel pseudo four component reaction.

Homoenolate generated from a,b-unsaturated aldehydes by NHC catalysis underwent facile addition to conjugated sul-fonimines, generated in situ, and subsequent methanolysis to afford protected GABA derivatives stereoselectively and in high yields, thus constituting a novel pseudo four component reaction. Ever since the original work on homoenolates...

A stereoselective Michael addition of homoenolate, generated from enals by nucleophilic heterocyclic carbene (NHC) catalysis, to beta-nitrostyrenes is reported for the first time. The products of this reaction obtained in good yields are of potential value in the synthesis of a variety of acyclic and heterocyclic compounds.

ChemInform 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.

A stereoselective Michael addition of homoenolate, generated from enals by nucleophilic heterocyclic carbene (NHC) catalysis, to -nitrostyrenes is reported for the first time. The products of this reaction obtained in good yields are of potential value in the synthesis of a variety of acyclic and heterocyclic compounds. The advent of homoenolate 1...

a b s t r a c t Transient zwitterion generated from allenoate and isoquinoline was successfully intercepted with cyano-acrylates and arylidenemalononitriles to devise a novel multicomponent reaction under mild conditions. The formation of transient zwitterions by the addition of nucle-ophilic species such as phosphines, isocyanides, N-heterocycles,...

a b s t r a c t Transient zwitterion generated from allenoate and isoquinoline was successfully intercepted with cyano-acrylates and arylidenemalononitriles to devise a novel multicomponent reaction under mild conditions. The formation of transient zwitterions by the addition of nucle-ophilic species such as phosphines, isocyanides, N-heterocycles,...

NBO analysis has been carried out for model molecules to elucidate the delocalization energies in phenylacetylenes and phenylvinylenes (which make up cruciform molecules). The model molecules considered are 1,2- , 1,3- and 1,4- positional isomers of bis(phenylethynyl)benzene, phenylethenyl -phenylethynylbenzene and bis(phenylethenyl)benzene which r...