New synthesis of flavanones catalyzed by l-proline

An efficient, green, and sustainable synthesis of new hybrid molecules containing flavanone with triazole by merging the Michael addition and Click reaction using a copper oxide/reduced graphene oxide nanocomposite in one pot is reported. The catalyst can easily be recycled and reused in seven consecutive runs without compromising the product yields. Other notable advantages include using water as a reaction medium and obtaining good to excellent yields, low catalyst loading, high atom efficiency, high substrate variation, and good results in the gram scale reaction.

Copper Oxide/Reduced Graphene Oxide Nanocomposite-Catalyzed Synthesis of Flavanones and Flavanones with Triazole Hybrid Molecules in One Pot: A Green and Sustainable Approach.

This review of simple indolizidine and quinolizidine alkaloids (i.e., those in which the parent bicyclic systems are in general not embedded in polycyclic arrays) is an update of the previous coverage in Volume 55 of this series (2001). The present survey covers the literature from mid-1999 to the end of 2013; and in addition to aspects of the isolation, characterization, and biological activity of the alkaloids, much emphasis is placed on their total synthesis. A brief introduction to the topic is followed by an overview of relevant alkaloids from fungal and microbial sources, among them slaframine, cyclizidine, Steptomyces metabolites, and the pantocins. The important iminosugar alkaloids lentiginosine, steviamine, swainsonine, castanospermine, and related hydroxyindolizidines are dealt with in the subsequent section. The fourth and fifth sections cover metabolites from terrestrial plants. Pertinent plant alkaloids bearing alkyl, functionalized alkyl or alkenyl substituents include dendroprimine, anibamine, simple alkaloids belonging to the genera Prosopis, Elaeocarpus, Lycopodium, and Poranthera, and bicyclic alkaloids of the lupin family. Plant alkaloids bearing aryl or heteroaryl substituents include ipalbidine and analogs, secophenanthroindolizidine and secophenanthroquinolizidine alkaloids (among them septicine, julandine, and analogs), ficuseptine, lasubines, and other simple quinolizidines of the Lythraceae, the simple furyl-substituted Nuphar alkaloids, and a mixed quinolizidine-quinazoline alkaloid. The penultimate section of the review deals with the sizable group of simple indolizidine and quinolizidine alkaloids isolated from, or detected in, ants, mites, and terrestrial amphibians, and includes an overview of the "dietary hypothesis" for the origin of the amphibian metabolites. The final section surveys relevant alkaloids from marine sources, and includes clathryimines and analogs, stellettamides, the clavepictines and pictamine, and bis(quinolizidine) alkaloids.

Simple indolizidine and quinolizidine alkaloids.

Recent advances in the preparation of bi- or poly-nuclear platinum complexes bridged only by alkynyl ligands are described. Emphasis is placed not only on the co-ordination modes of alkynyl ligands but also on their migration and chemical activation.

Synthesis, structure and reactivity of homo- and hetero-polynuclear complexes of platinum bearing CCR groups as unique bridging ligands

Gold-catalyzed intermolecular oxidation of chiral homopropargyl sulfonamides: a reliable access to enantioenriched pyrrolidin-3-ones

Regioselective aldol reaction of dianion 1 with aldehyde 5 provides the basis of a new approach to the construction of polyhydroxy indolizidines and the application of this methodology to the synthesis of 8-epicastanospermine 11 and 1,8,8a-triepicastanospermine 12 is described.

N-substituted pyrrolidin-3-ones as heterocyclic building blocks. Enantioselective synthesis of 8-epi- and 1,8,8a-triepi-castanospermine

The synthesis and mercury(II) trifluoroacetate mediated transformation of 3-bromo-1-phenylprop-2-ynyl aryl ethers to flavanones is reported.

Mercury(II) trifluoroacetate-mediated transformation of 3-bromo-1-phenylprop-2-ynyl aryl ethers; a novel synthesis of flavanones

Reduction of heterocyclic-derived aldol adducts 2 and 3 using NaBH(OAc)3 is stereoselective and proceeds via a hydroxy-directed mechanism to give 6 and 7, respectively, thereby complementing the stereoselectivity available with NaBH4; a synthesis of (+)-8,8a-diepicastanospermine 11 from diol 6 is described.

R. Sankara Subramanian

Papers

N-substituted pyrrolidin-3-ones as heterocyclic building blocks. Enantioselective synthesis of 8-epi- and 1,8,8a-triepi-castanospermine

Mercury(II) trifluoroacetate-mediated transformation of 3-bromo-1-phenylprop-2-ynyl aryl ethers; a novel synthesis of flavanones

Hydroxy-directed ketone reduction. Application to the synthesis of (+)-8,8a-diepicastanospermine