Herein, we report the accomplishment of Rh(II)-catalyzed intramolecular amination of aryl azide-tethered 1,3-dicarbonyls to access privileged heterocyclic scaffolds with exclusive diastereoselectivity under simple reaction conditions. This method also allows an unconventional direct α-amination at electron-deficient C(sp)-H bonds of aryl azide-tethered 1,3-diketones to afford fused 2-azatricyclo[4.4.
View Article and Find Full Text PDFThe intermolecular transformation of simple substrates into highly functionalized scaffolds with multiple stereogenic centers is an attractive strategy in modern organic synthesis. Prochiral 2,5-cyclohexadienones, being stable and easily accessible, are privileged key building blocks for the synthesis of complex molecules and bioactive natural products. In particular, -quinols and -quinamines are important subclasses of cyclohexadienones, having both nucleophilic and electrophilic sites, and can undergo various intermolecular cascade annulations formal cycloadditions and other transformations.
View Article and Find Full Text PDFThe amide bond is prominent in natural and synthetic organic molecules endowed with activity in various fields. Among a wide array of amide synthetic methods, substitution on a pre-existing (O)C-N moiety is an underexplored strategy for the synthesis of amides. In this work, we disclose a new protocol for the defluorinative arylation of aliphatic and aromatic trifluoroacetamides yielding aromatic amides.
View Article and Find Full Text PDFHere in the present manuscript, we report our observation of an unprecedented stereoselective synthesis of 2-isoindolin-1,3-ylidenes from 2-(formylphenyl)acrylates and phenacylazide in the presence of piperidine. Unlike in our previous findings, in which we accessed 3-keto-isoquinolines from the same starting materials under slightly modified reaction conditions, this unexpected one-pot tandem reaction allows an efficient and simple method to access a variety of highly functionalized ethyl ()-2-(()-3-(2-oxo-2-arylethylidene)-2,3-dihydro-1-benzo[]isoindol-1-ylidene)-acetates in very good to excellent yields (up to 91%). The present methodology is compatible with a wide variety of functional groups.
View Article and Find Full Text PDFThe development of transition-metal catalyzed enantioselective and diastereoselective transformations has contributed many advances in the field of synthetic organic chemistry. Particularly, stereoselective desymmetrization of prochiral cyclohexadienones represents a powerful strategy for accessing highly functionalized and stereochemically enriched scaffolds, which are often found in biologically active compounds and natural products. In recent years, several research groups including our group have made a significant progress on transition-metal catalyzed stereoselective desymmetrizations of 2,5-cyclohexadienones.
View Article and Find Full Text PDFAn efficient and transition-metal-free strategy for the synthesis of 3-keto-isoquinolines in one pot has been developed from the easily accessible 2-(formylphenyl)acrylates and phenacyl azides. Various substituted aldehydes and phenacyl azides were successfully employed in this transformation to furnish a variety 3-keto-isoquinolines in very good yields. A number of controlled experiments were conducted to postulate the reaction mechanism.
View Article and Find Full Text PDFCorrection for 'Magnetically recoverable Cu/FeO catalyzed highly regioselective synthesis of 2,3,4-trisubstituted pyrroles from unactivated terminal alkynes and isocyanides' by Dipak Kumar Tiwari et al., Chem. Commun.
View Article and Find Full Text PDFAn efficient and transition-metal-free approach for the synthesis of 4-arylquinolines from readily available anilines and alkynes in the presence of KSO and DMSO has been developed. A variety of alkynes and anilines having a diverse range of substitution patterns can undergo the one-pot cascade process successfully. Effectively, this method uses DMSO as one carbon source, thus providing a highly atom-economical and environmentally benign approach for the synthesis of 4-arylquinolines.
View Article and Find Full Text PDFA transition-metal-free method for the construction of functionalized quinolines from readily available acetophenones and anthranils is reported. This one-pot reaction cascade involves in situ generation of α,β-unsaturated ketones from the acetophenone via one-carbon homologation by DMSO followed by the aza-Michael addition of anthranils and subsequent annulation. DMSO acted in this reaction not only as solvent but also as one carbon source, thus providing a highly atom-economical and environmentally benign approach for the synthesis of 3-substituted quinolines.
View Article and Find Full Text PDFChem Commun (Camb)
May 2017
An efficient method to access functionalized quinolines from the readily available saturated ketones and anthranils has been explored. This one-pot cascade reaction involves the in situ generation of α,β-unsaturated ketones by the copper catalysed dehydrogenation of saturated ketones followed by the aza-Michael addition of anthranils and subsequent annulation.
View Article and Find Full Text PDFAn efficient, one pot tandem nano Cu(0)/Fe3O4 catalyzed highly regioselective synthesis of 3-substituted pyrrole-2,4 dicarboxylates from unactivated terminal alkynes and isocyanides has been developed. This strategy exhibits an unprecedented double addition of isocyanides on unactivated terminal alkynes to obtain trisubstituted pyrroles in high yields. Furthermore, the catalyst was magnetically recovered and reused five times without any appreciable loss of activity.
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