Visible light induced cyclopropanation of dibromomalonates with alkenes via double-SET by photoredox catalysis.

We report herein a visible light induced generation of a carbanion via double-SET and its application in cyclopropanation of alkenes. This new synthetic approach to form cyclopropane derivatives was conducted under mild conditions, using sunlight in open air, showing the features such as environmental benignness and an easy to handle procedure.

Efficient synthesis of 1,2-bis(alkoxycarbonyl)pyrazol-3-ones from 2,3-allenoic acids, azodicarboxylates and PPh3.

An efficient cascade reaction of 2,3-allenoic acids with dialkyl azodicarboxylate in the presence of PPh3 affording 1,2-bis(alkoxycarbonyl)pyrazol-3-ones in moderate yields has been developed. The reaction may proceed via the intramolecular Michael addition of the expected 2,3-allenoyl hydrazines.

Amine-catalyzed direct photoarylation of unactivated arenes.

Constructing biaryls through direct aromatic C-H functionalization of unactivated arenes has become a popular topic in organic chemistry. Many efficient methods have been developed. In this Communication, a direct arylation of unactivated arenes with a broad range of aryl iodides is reported. This reaction proceeds through a new type of amine-catalyzed single electron transfer initiated radical coupling procedure to form biaryls in high yields under UV irradiation at room temperature. Only 20 mol% of TMEDA is used as the catalyst. No other additives are required for this transformation, thus avoiding the use of toxic transition metal catalysts, strong bases, or large amounts of other organic additives. This greener protocol provides a new strategy to achieve direct aromatic C-H functionalization and offers a new example of cost-effective and environmentally benign access to biaryls.

Synthesis of carboxylate-functionalized graphene nanosheets for high dispersion of platinum nanoparticles based on the reduction of graphene oxide via 1-pyrenecarboxaldehyde.

A one-step reduction/functionalization strategy for the synthesis of carboxylate-functionalized graphene nanosheets is reported in this paper. 1-pyrenecarboxaldehyde (PCA) is introduced as a new reductant for the chemical reduction of graphene oxide (GO), serving three roles: reducing GO to graphene nanosheets (GNs), stabilizing the as-prepared GNs due to the electrostatic repulsion of the oxidation products of PCA (1-pyrenecarboxylate, PC⁻) on the surface of the GNs and anchoring Pt nanoparticles (Pt NPs) with high dispersion and small particle size. Transmission electron microscopy shows that Pt NPs with an average diameter of 1.3 ± 0.2 nm are uniformly dispersed on the surface of the PC⁻-functionalized GNs (PC⁻-GNs). The obtained Pt NPs/PC⁻-GNs nanohybrids have higher electrocatalytic activity and stability towards methanol oxidation in comparison with Pt NPs supported on GNs obtained by the chemical reduction of GO with the typical reductant, hydrazine.

(7R,8S,9S,12S)-1-Benz-yloxy-13,14-didehydro-12-hy-droxy-2,13-dimeth-oxy-N-methyl-morphinane.

In the title compound, C(26)H(31)NO(4), a sinomenine derivative, the angle between the two aromatic rings is 53.34 (4)°. The N-containing ring is in a chair conformation, while the other two non-planar rings are in a half-boat conformation. In the crystal, mol-ecules are linked by O-H⋯N inter-actions into a C(8) chain along [100].

(7R,8S,9S,12S)-1-(4-Chloro-benz-yloxy)-13,14-didehydro-12-hy-droxy-2,13-dimeth-oxy-N-methyl-morphinane.

The title compound, C(26)H(30)ClNO(4), a sinomenine derivative, has five six-membered rings, two of which are aromatic, with a dihedral angle of 34.13 (20)° between these. The N-containing ring and the fourth ring exhibit chair conformations, while the fifth ring approximates an envelope conformation. A single inter-molecular O-H⋯N hydrogen-bonding inter-action gives a one-dimensional chain structure which extends along the a axis. The absolute configuration for the mol-ecule has been determined.

(9S,13R,14S)-7,8-Didehydro-4-(4-fluoro-benz-yloxy)-3,7-dimeth-oxy-17-methyl-morphinan-6-one sesquihydrate.

In the title sinomenine derivative, C(26)H(28)FNO(4)·1.5H(2)O, the dihedral angle between the two aromatic rings is 55.32 (6)°. The N-containing ring has an approximate chair conformation, while other two rings have approximate envelope and half-chair conformations. One water mol-ecule is located on a twofold symmetry axis. In the crystal, the water mol-ecules form O-H⋯O and O-H⋯N hydrogen bonds, bridging symmetry-related main mol-ecules.

(8S,9S,10R)-4-(4-Chloro-benz-yloxy)-7,8-didehydro-3,7-dimeth-oxy-17-methyl-morphinan-6-one monohydrate.

In the title compound, C(26)H(28)Cl(N)O(4)·H(2)O, the dihedral angle betwene the two aromatic rings is 69.73 (6)°. The N-containing ring exhibits a chair conformation, while the other non-aromatic rings are in approximate envelope conformations. In the crystal, the water mol-ecule forms O-H⋯O and O-H⋯N hydrogen bonds and a C-H⋯O link also occurs.

Chiral N-heterocyclic carbene catalyzed annulation of α,ß-unsaturated aldehydes with 1,3-dicarbonyls.

Chiral N-heterocyclic carbene catalyzed annulations of ynals and enals with 1,3-dicarbonyls have been described. The two reactions provided direct and efficient methods for enantioselective synthesis of functionalized dihydropyranones. Comparatively, the reactions starting from ynals were atom-economical; furthermore the reactions of enals demonstrated broader substrate compatibility.

(9S,13R,14S)-7,8-Didehydro-4-(4-iodo-benz-yloxy)-3,7-dimeth-oxy-17-methyl-morphinan-6-one monohydrate.

In the title compound, C(26)H(28)INO(4)·H(2)O, benzene rings are inclined at a dihedral angle of 69.9 (1)°. The N-containing ring exhibits a chair conformation, while the other rings approximate to envelope conformations. In the crystal, the uncoordinated water mol-ecule forms inter-molecular O-H⋯O and O-H⋯N hydrogen bonds.