Copper-catalyzed intermolecular formal (5 + 1) annulation of 1,5-diynes with 1,2,5-oxadiazoles.

One-carbon homologation reactions based on one-carbon insertion into the N-O bond of heterocycles have received tremendous interest over the past decades. However, these protocols have to rely on the use of hazardous and not easily accessible diazo compounds as precursors, and examples of the relevant asymmetric catalysis have not been reported. Here we show that a copper-catalyzed intermolecular formal (5 + 1) annulation of 1,5-diynes with 1,2,5-oxadiazoles involving one-carbon insertion into the heterocyclic N-O bond via non-diazo approach.

Copper-Catalyzed Tandem Cyclization/Direct C(sp)-H Annulation of Azide-Ynamides via α-Imino Copper Carbenes: Access to Azepino[2,3-:4,5-']diindoles.

A novel copper-catalyzed tandem cyclization/direct C(sp)-H annulation of phenyl azide-ynamides via α-imino copper carbenes has been developed, which provides a concise and flexible approach for the construction of a range of valuable azepino[2,3-:4,5-']diindoles in mostly good to excellent yields with high chemoselectivities. This tandem reaction also exhibits a broad substrate scope, excellent functional group tolerance, simple operation, and mild reaction conditions.

I -Catalyzed Cycloisomerization of Ynamides: Chemoselective and Divergent Access to Indole Derivatives.

Herein, an I -catalyzed unprecedented cycloisomerization of ynamides is developed, furnishing various functionalized bis(indole) derivatives in generally good to excellent yields with wide substrate scope and excellent atom-economy. This protocol not only represents the first molecular-iodine-catalyzed tandem complex alkyne cycloisomerizations, but also constitutes the first chemoselective cycloisomerization of tryptamine-ynamides involving distinctively different C(sp )-C(sp ) bond cleavage and rearrangement. Moreover, chiral tetrahydropyridine frameworks containing two stereocenters are obtained with moderate to excellent diastereoselectivities and excellent enantioselectivities.

Highly Site-Selective Oxidative Cyclization of Ene-ynamides via Non-Noble-Metal Catalysis: Access to Functionalized Lactams.

Herein, an unprecedented non-noble-metal-catalyzed oxidation/cyclization of ene-ynamides is developed, allowing the synthesis of diversely functionalized lactams in moderate to good yields with excellent diastereoselectivities without the observation of typical cyclopropanation products. In combination with Ellman's -butylsulfinimine chemistry, chiral γ-lactams containing three contiguous stereocenters are obtained with high diastereo- and enantioselectivity. Moreover, density functional theory (DFT) calculations indicate that this protocol probably undergoes a carbon cation or proton transfer process.

Enantioselective Rh-Catalyzed Azide-Internal-Alkyne Cycloaddition for the Construction of Axially Chiral 1,2,3-Triazoles.

Significant advances have been achieved for the construction of chiral skeletons containing 1,2,3-triazoles via transition-metal-catalyzed asymmetric azide-alkyne cycloaddition; however, most of them have been limited to terminal alkynes in the synthesis of central chirality via desymmetrization and dynamic/dynamic kinetic resolution. Enantioselective transition-metal-catalyzed azide-internal-alkyne cycloaddition is extremely limited. Moreover, the construction of a challenging five-membered (hetero)biaryl axially chiral molecule via transition-metal-catalyzed asymmetric azide-internal-alkyne cycloaddition is still underexplored.

Facile synthesis of α-alkoxyl amides scandium-catalyzed oxidative reaction between ynamides and alcohols.

A novel and efficient scandium-catalyzed oxidative reaction between ynamides and alcohols for the facile synthesis of various α-alkoxyl amides is reported in this paper. The reaction avoids the need for the use of α-diazo carbonyls which are unstable and may cause some safety concerns. Instead, by using alkynes as the starting materials, this protocol features readily available substrates, compatibility with a broad range of functional groups, simple procedure, mild reaction conditions, and high chemoselectivity.

1-Cyano-methyl-1,4-diazo-niabicyclo-[2.2.2]octane tetra-chloridocadmate(II).

In the title salt, (C(8)H(15)N(3))[CdCl(4)], four Cl atoms coordinate the Cd(II) atom in a slightly distorted tetra-hedral geometry. In the crystal, each [CdCl(4)](2-) anion is connected to the 1-cyano-methyl-1,4-diazo-niabicyclo-[2.2.

(4-Aza-1-azoniabicyclo-[2.2.2]octane-κN(4))trichloridocobalt(II).

In the title compound, [CoCl(3)(C(6)H(13)N(2))], the tetra-hedrally coordinated Co(II) ion has Co-Cl distances ranging from 2.2220 (11) to 2.2449 (9) Å and a Co-N distance of 2.

1-Cyano-methyl-1,4-diazo-niabicyclo-[2.2.2]octane tetra-chloridocobaltate(II).

In the title salt, (C(8)H(15)N(3))[CoCl(4)], the four chloride anions coordinate the Co(II) ion in a distorted tetra-hedral geometry. In the crystal, N-H⋯Cl hydrogen bonds link cations and anions into chains running along the c axis. The crystal packing is further stabilized by weak C-H⋯Cl and C-H⋯N inter-actions.