Samarium(III)-Catalyzed C(sp3)–H Bond Activation: Synthesis of Indolizines via C–C and C–N Coupling between 2-Alkylazaarenes and Propargylic Alcohols

Synthesis of fused tricyclic indolizines by intramolecular silver-mediated double cyclization of 2-(pyridin-2-yl)acetic acid propargyl esters

A silver-mediated intramolecular double cyclization of 2-(pyridin-2-yl)acetic acid propargyl esters for the synthesis of fused tricyclic indolizines is reported.

Palladium-Catalyzed Synthesis of 5-Iminopyrrolones through Isocyanide Double Insertion Reaction with Terminal Alkynes and Water

With the combination of Pd(dppf)Cl₂ and Cu(OAc)₂, a variety of 5-iminopyrrolones were synthesized in moderate to good yields from terminal alkynes, isocyanide, and water via isocyanide double insertion and cycloaddition reaction. A plausible reaction mechanism for this process is depicted. Furthermore, selected compounds 3c, 3e, and 3h exhibited good activities against HepG2 (human liver cancer), NCI-H460 (human lung cancer), and SK-OV-3 (human ovarian cancer) cell lines with IC₅₀ values in the range of 10.63-22.63 μmol L^-1.

Facile Synthesis of Azaarene-Substituted Hydroxycoumarins Possessing High Biological Activities via Three-Component C(sp(3))-H Functionalization

An unprecedented three-component C(sp(3))-H functionalization of 2-alkylazaarenes with aryl aldehydes and 4-hydroxycoumarins was realized, providing azaarene-substituted 3-benzyl-4-hydroxycoumarins in good to excellent yields. These new target compounds displayed broad-spectrum antibacterial activities, providing a new type of antibacterial skeleton.

A novel coupling reaction of α-halo ketones promoted by SmI3/CuI

In the presence of SmI₃ and catalyzed by CuI in DMF, α-haloketones were transformed unexpectedly into α-hydroxy-1,4-diketones. The mechanism was probed and DMF was assumed to play a dual role both as a hydroxyl source and as a solvent.

Cu(i)-catalyzed multicomponent cascade reactions of terminal alkynes, unactivated primary alkyl bromides, CO2 and NaN3

We have developed a mild, robust, and multicomponent cascade reaction for the synthesis of triazolo-fused dihydrooxazinones from terminal alkynes, unactivated primary alkyl bromides, carbon dioxide and sodium azide.

Heterobimetallic dinuclear lanthanide alkoxide complexes as acid–base bifunctional catalysts for synthesis of carbamates under solvent-free conditions

Heterobimetallic dinuclear lanthanide alkoxide complexes Ln₂Na₈(OCH₂CH₂NMe₂)₁₂(OH)₂ [Ln: I (Nd), II (Sm), III (Yb) and IV (Y)] were used as efficient acid–base bifunctional catalysts for the synthesis of carbamates and the N-Boc protection of amines.

Capture of CO2 in air for 4,5-disubstituted furan-2(5H)-ones

A sustainable strategy for the assembly of 4,5-disubstituted furan-2(5H)-ones directly from carbon dioxide from air was developed.

Recent advances in the synthesis of indolizines and their π-expanded analogues

Synthesis of indolizines developed during the last decade is reviewed, with special emphasis given to densely functionalized architectures, breakthrough strategies, compounds bearing electron-donating and electron-withdrawing substituents and π-expanded systems.

An efficient five-component synthesis of thioether containing dihydropyrano[2,3-c]pyrazoles: a green domino strategy

A one-pot, five component domino synthesis of novel thioether containing dihydropyrano[2,3-c]pyrazoles under solvent-free and catalyst-free conditions is demonstrated.

Au-catalyzed ring-opening reactions of 2-(1-alkynyl-cyclopropyl)pyridines with nucleophiles

A novel method for the C-C bond cleavage of cyclopropanes was developed by gold-catalyzed cycloisomerization of 2-(1-alkynyl-cyclopropyl)pyridine with nucleophiles, which provides efficient access to structurally diverse indolizines under mild conditions. A series of N-, C- and O-based nucleophiles were involved in this reaction to afford the corresponding indolizines in modest to excellent yields.

Sc(OTf)3-mediated 1,3-dipolar cycloaddition-ring cleavage-rearrangement: a highly stereoselective access to Z-β-enaminonitriles

A novel and highly stereoselective synthesis of Z-β-enaminonitriles from azides and α,β-unsaturated nitriles is reported. The reaction proceeds via a 1,3-dipolar cycloaddition-ring cleavage-rearrangement cascade mediated by a catalytic amount of Sc(OTf)3. A plausible reaction mechanism for this process is depicted.

One-pot synthesis of indolizine via 1,3-dipolar cycloaddition using a sub-equivalent amount of K2Cr2O7 as an efficient oxidant under base free conditions

X = Cl or Br; EWG₁, EWG₂ = electron withdrow group, one-pot reaction, 29 examples, yields from moderate to high, gram scale-up potential confirmed.

Palladium-catalyzed highly efficient synthesis of functionalized indolizines via cross-coupling/cycloisomerization cascade

Pd-catalyzed cross-coupling/cycloisomerization of 3-(2-pyridyl) propargyl carbonates with organoboronic acids provides a straightforward route for the synthesis of 1,3-disubstituted indolizines.

Indium-catalyzed C(sp3)–H functionalization of 2-methylazaarenes through direct benzylic addition to trifluoromethyl ketones

The application of InCl₃ for the catalytic C(sp³)–H functionalization of 2-methylazaarenes leading to trifluoromethylated alcohols in up to 99% yield.

Utilization of methylarenes as versatile building blocks in organic synthesis

This review attempts to describe the latest developments in the utilisation of methylarenes adopting C–H functionalization strategies and covers all the developments until March 2015.

Indolizine synthesis via Cu-catalyzed cyclization of 2-(2-enynyl)pyridines with nucleophiles

Cu-catalyzed cyclization of 2-(2-enynyl)pyridines with various nucleophiles was developed, providing efficient access to indolizine derivatives.

Molybdate sulfuric acid (MSA): an efficient reusable catalyst for the synthesis of tetrahydrobenzo[4,5]imidazo[2,1-b]quinazolin-1(2H)-ones under solvent-free conditions and evaluation of their in vitro bioassay

The attractive features of this methodology are green and easy workability with high product yields. All the title compounds have good to excellent anti-oxidant and anticancer activity.

Copper-mediated synthesis of pyrazolo[1,5-a]pyridines through oxidative linkage of C–C/N–N bonds

Copper-mediated synthesis of pyrazolo[1,5-a]pyridine-3-carboxylates through oxidative linkage of C–C and N–N bonds under mild reaction conditions with broad substrate scope is described.

Silver-Mediated Synthesis of Indolizines via Oxidative C-H functionalization and 5- endo-dig cyclization

An efficient strategy for the synthesis of indolizines from readily available starting materials via oxidative C-H functionalization and 5-endo-dig cyclization in one step has been demonstrated. This protocol represents wide substrate scope, high functional group tolerance and selectivity. The structure of the product was confirmed by the X-ray crystallographic studies. The Ag₂CO₃ required of this tandem reaction can be recycled and reused after undergoing oxidative reaction.

Hyperbranched polyester nanorods with pyrrolo[2,1-a]isoquinoline end groups for fluorescent recognition of Fe3+

Novel hyperbranched polyester nanorods HBPE-CICA₆ and HBPE-CICA₂ were obtained and used to establish a highly sensitive fluorescent sensor for Fe³⁺ ions.