Shengyang Ni

Oxidative Difunctionalization of Alkynoates through Alkylation and Migration Decarboxylative Arylation

A cascade oxidative difunctionalization reaction of alkynoates for the construction of trisubstituted olefins has been developed. The process undergoes alkylation of a C-C triple bond, 1,4-aryl migration, and decarboxylation, which demonstrates a multistep radical cascade reaction for the difunctionalization of alkynoates and also represents a strategy of direct decarboxylation of esters.

Hydroxyalkylation-initiated radical cyclization of N-allylbenzamide for direct construction of isoquinolinone.

A metal-free hydroxyalkylation-initiated radical six-membered heterocycle formation reaction of N-allylbenzamide is developed. This reaction proceeds through C(sp(3))-H bond cleavage, oxyalkylation of the double bond, and intramolecular cyclization, which provides a new route toward 4-substituted 3,4-dihydroisoquinolin-1(2H)-one derivatives.

Metal-Free Oxidative Functionalization of a C(sp3)–H Bond Adjacent to Nitrogen and Intramolecular Aromatic Cyclization for the Preparation of 6-Amidophenanthridines

A metal-free cyclization reaction of 2-isocyanobiphenyls with amide derivatives by using tert-butyl peroxybenzoate (TBPB) as oxidant was developed, which provided an access to pharmacologically interesting 6-amidophenanthridine compounds. The reactions proceeded through a sequence of functionalization of the C(sp(3))-H bond adjacent to the nitrogen atom and intramolecular radical aromatic cyclization with good chemistry yields.

Ni-Catalyzed Reductive Cross-Coupling of Amides with Aryl Iodide Electrophiles via C–N Bond Activation

A Ni-catalyzed reductive cross-coupling reaction between two electrophiles, amides and aryl iodides, has been developed. This work is the first example using amide as an electrophile to couple with another electrophile, instead of using highly basic and pyrophoric nucleophiles. Furthermore, the Ni catalyst chemoselectively inserting the C-N bond of amide triggered the reductive cross-coupling reaction, which solves the problem that the Ni catalyst preferentially inserts the more reactive C-I bond to form a self-coupling product.

Sunlight-promoted cyclization versus decarboxylation in the reaction of alkynoates with N-iodosuccinimide: easy access to 3-iodocoumarins

A sunlight-initiated radical conversion of aryl alkynoates to 3-iodocoumarins has been achieved using N-iodosuccinimide as the iodine source without the use of a catalyst or additive. Experimental, X-ray analysis, and computational studies indicate that the reaction under sunlight proceeds through iodination, spirocyclization and ring expansion to form the kinetic product. The sunlight-driven reaction provides a green pathway to especially valuable 3-halocoumarins derivatives.

N-Iodosuccinimide-Promoted Cascade Trifunctionalization of Alkynoates: Access to 1,1-Diiodoalkenes

An efficient cascade trifunctioalization reaction of alkynoates with N-iodosuccinimide has been developed which proceeds through iodination, aryl migration, decarboxylation, and second iodination. This reaction represents an example of 1,1-difunctionalization of the acetylene bond and also provides a new strategy for the preparation of 1,1-diiodoalkenes.

Photoredox-Catalyzed Cascade Difluoroalkylation and Intramolecular Cyclization for Construction of Fluorinated γ-Butyrolactones

A cascade visible-light photocatalytic difluoroalkylation and intramolecular cyclization reaction has been developed for the synthesis of difluoroalkylated oxygen heterocycles. The reaction was carried out under very mild conditions, affording fluorinated isobenzofuran-1-ones, lactone, and cyclic ethers with up to 97% chemical yields. Furthermore, several types of bromofluoroalkane precursors bearing ester, keto, amido, and phosphate groups could all work very well in this reaction, which provides an easy method for the preparation of functionalized difluoroalkylated oxygen heterocycles.

Access to Alkyl-Substituted Lactone via Photoredox-Catalyzed Alkylation/Lactonization of Unsaturated Carboxylic Acids

An efficient photoredox-catalyzed alkylation/lactonization reaction of unsaturated carboxylic acids by using alkyl N-hydroxyphthalimide esters as alkylation reagents has been developed. Varieties of redox-active esters derived from aliphatic carboxylic acids were proved viable in this method, affording alkyl substituted lactones in moderate to good yields. This redox-neutral procedure features mild conditions and operational simplicity, which provides a new strategy for the synthesis of alkyl substituted lactones.