Copper-Catalyzed Aerobic Enantioselective Cross-Dehydrogenative Coupling of N-Aryl Glycine Esters with Terminal Alkynes

Cu(ii)- or Co(ii)-Catalyzed C(SP3)–H oxidation of N,N-dimethylaminoethanol: facile synthesis of methylene-bridged biindoles and 3-formylindoles selectively

Methylene-bridged biindoles and 3-formylindoles were synthesized with high conversion rate and good regioselectivity using a new carbon donor N,N-dimethylethanolamine, catalyzed by CuCl₂ and CoCl₂ respectively.

Bimolecular oxidative C–H alkynylation of α-substituted isochromans

The first bimolecular oxidative C–H functionalization of secondary benzylic ethers for tertiary ether synthesis has been established in high efficiency.

An Enantioselective Cross-Dehydrogenative Coupling Catalysis Approach to Substituted Tetrahydropyrans

An enantioselective cross-dehydrogenative coupling (CDC) reaction to access tetrahydropyrans has been developed. This process combines in situ Lewis acid activation of a nucleophile in concert with the oxidative formation of a transient oxocarbenium electrophile, leading to a productive and highly enantioselective CDC. These advances represent one of the first successful applications of CDC for the enantioselective couplings of unfunctionalized ethers. This system provides efficient access to valuable tetrahydropyran motifs found in many natural products and bioactive small molecules.

Efficient access to chiral benzo[c]chromenes via asymmetric transfer hydrogenation of ketals

A highly enantioselective method to chiral α-substituted 6H-benzo[c]chromenes through chiral imidodiphosphoric acid-catalyzed asymmetric transfer hydrogenation of ketals has been established.

Visible light-induced aerobic oxidative cross-coupling of glycine derivatives with indoles: a facile access to 3,3′ bisindolylmethanes

A rapid synthesis of 3,3′-bisindolylmethanes is achieved via a photocatalyzed double Friedel–Crafts alkylation reaction between glycine derivatives and indoles.

Metal-free photocatalyzed aerobic oxidative Csp3–H functionalization of glycine derivatives: one-step generation of quinoline-fused lactones

This reaction provides facile access to a series of valuable quinoline-fused lactones at room temperature under an air atmosphere.

Visible light-induced aerobic oxidative cross-coupling of glycine esters with α-angelicalactone: a facile pathway to γ-lactams

A rapid synthesis of substituted γ-lactams is achieved via metal-free photocatalyzed aerobic oxidative dehydrogenative formal [2 + 3] cyclization of glycine esters with α-angelicalactone.

Auto-oxidation promoted sp3 C–H arylation of glycine derivatives

An auto-oxidation promoted sp³ C–H arylation reaction between N-aryl glycine derivatives and electron-rich arenes, leading to the formation of N-aryl α-aryl α-amino acid derivatives, is described. This atom-economical and environmentally benign reaction proceeds smoothly under mild reaction conditions and requires only Brønsted acid and oxygen (balloon). A plausible radical involved mechanism is proposed.

Cross-dehydrogenative coupling and oxidative-amination reactions of ethers and alcohols with aromatics and heteroaromatics

Cross-dehydrogenative coupling (CDC) is a process in which, typically, a C-C bond is formed at the expense of two C-H bonds, either catalyzed by metals or other organic compounds, or via uncatalyzed processes. In this perspective, we present various modes of C-H bond-activation at sp3 centers adjacent to ether oxygen atoms, followed by C-C bond formation with aromatic systems as well as with heteroaromatic systems. C-N bond-formation with NH-containing heteroaromatics, leading to hemiaminal ethers, is also an event that can occur analogously to C-C bond formation, but at the expense of C-H and N-H bonds. A large variety of hemiaminal ether-forming reactions have recently appeared in the literature and this perspective also includes this complementary chemistry. In addition, the participation of C-H bonds in alcohols in such processes is also described. Facile access to a wide range of compounds can be attained through these processes, rendering such reactions useful for synthetic applications via Csp3 bond activations.

Facile Construction of Quinoline-2-carboxylate Esters through Aerobic Oxidation of Alkyl 4-Anilinocrotonates Induced by a Radical Cation Salt

A facile construction of quinoline-2-carboxylate esters through an aerobic oxidation of alkyl 4-anilinocrotonates is described. In the presence of dioxygen, sp³ C-H bonds in 4-anilinocrotonates can easily be oxidized by using a catalytic amount of a radical cation salt, providing a radical intermediate. After further oxidation and domino cyclization, the desired quinoline derivatives were afforded in high yields. This reaction provides a new way to construct the pharmaceutically relevant quinoline skeleton, avoiding harsh reaction conditions and tedious starting material synthesis.

Oxidative cross-coupling reaction by scandium catalysis for synthesis of α-alkyl α-amino acid ester derivatives

A novel oxidative cross-coupling reaction between N-arylglycine esters and alkyl boronic acid esters was developed by scandium catalysis.

Visible-Light-Induced Photocatalytic Aerobic Oxidative Csp3-H Functionalization of Glycine Derivatives: Synthesis of Substituted Quinolines

A visible-light induced photocatalytic aerobic oxidative dehydrogenative coupling/aromatization tandem reaction of glycine esters with unactivated alkenes has been accomplished. This visible light-driven protocol has been successfully applied to a broad scope of glycine esters and simple alkenes, giving rise to diverse substituted quinoline derivatives in 18-84% yield under mild (at room temperature under air atmosphere) and operationally simple reaction conditions.

Iron-catalyzed oxidative sp3 carbon–hydrogen bond functionalization of 3,4-dihydro-1,4-benzoxazin-2-ones

Iron-catalyzed sp³ C–H bond functionalization of benzoxazinones has been developed and applied for the synthesis of natural product cephalandole A.