A New Entry to Cascade Organocatalysis: Reactions of Stable Sulfur Ylides and Nitroolefins Sequentially Catalyzed by Thiourea and DMAP

Abstract

A novel cascade organocatalysis that allows efficient and rapid access to diverse and structurally complex oxazolidin-2-ones from simple starting materials and catalysts has been developed. A possible mechanism of this reaction has been proposed based on D- and 13C-labeling experiments.

Comparisons of Halogenated β-Nitrostyrenes as Antimicrobial Agents

“…They proposed that β-nitrostyrene acts as a reversible inhibitor of this enzyme by interaction and formation of a covalent complex via nucleophilic attack of PTP1B cysteine on the β-nitro group at the catalytic site. However, sulphur ylides, like thiol nucleophiles, are found to undergo Michael addition to a wide range of β-nitrostyrenes [23][24][25][26]. The known reactivity of β-nitrostyrenes with sulfhydryl groups is consistent with these observations.…”

Asymmetric trapping of zwitterionic intermediates by sulphur ylides in a palladium-catalysed decarboxylation-cycloaddition sequence

“…More importantly, their synthetic potential has been well demonstrated in the synthesis of numerous bioactive natural products and pharmaceuticals 6,9,10 . In the past decade, the cycloaddition chemistry of sulphur ylides has evolved dramatically beyond three-membered rings, largely as a consequence of the valuable contributions made by Aggarwal and co-workers [11][12][13][14][15][16][17][18][19][20][21][22] , among others. For instance, in 2006, Aggarwal's group developed an elegant epoxy-annulation sequence reaction of vinyl sulphonium salts, which are important precursor of sulphur ylides, to rapidly convert aminoaldehydes, ketones and imines into epoxide-fused heterocycles (Fig.…”

“…In the same year, our own group developed a cascade reaction involving acyl-stabilized sulphur ylides and nitroolefins-specifically, a [4 þ 1] cycloaddition/rearrangement cascade (Fig. 1c) [15][16] . Notably, chiral H-bonding catalysis was successfully applied to this transformation, affording enantio-enriched oxazolidin-2-one products in good efficiency and selectivity.…”

“…In the past several years, we are interested in carbo-and heterocycle synthesis by using acyl-stabilized sulphur ylides 12,15,16,[27][28][29] . We herein describe an unprecedented Pdcatalysed DC reactions of vinyl benzoxazinanones by using sulphur ylides to highly enantioselectively trap Pd-stabilized zwitterionic intermediates I (Fig.…”

Enantiodivergente Organokaskadenreaktionen

“…Für die kommenden Jahre ist die Einführung weiterer Organokatalysatoren neben den weit verbreiteten Prolinderivaten zu erwarten. Viele Organokatalysatoren auf der Basis von Cinchona-Alkaloiden, Binol oder Thioharnstoff werden heute erfolgreich in der Organokatalyse angewendet, finden aber in Kaskadensequenzen bislang selten Gebrauch, [6,15,16] was aber die Aussicht auf spektakuläre Anwendungen keinesfalls schmälert Umgekehrt sollte man nicht erwarten, dass Organokaskadensequenzen in der nahen Zukunft klassische mehrstufige Synthesen gänzlich ersetzen werden. Dennoch wird die rasche Fortentwicklung dieses Gebiets helfen, zu kürzeren und schnelleren Verfahren für die Synthese komplexer Moleküle, insbesondere von Naturstoffen, zu gelangen und weitere Annährungen an die Multienzym-katalysierten Umsetzungen gestatten.…”