Organocatalytic Enantioselective Dehydrogenativeα-Alkylation of Aldehydes with Benzylic Compounds

Brønsted Acid-Catalyzed Minisci-Type Cross-Dehydrogenative Coupling of N-Heteroaromatics and Cyclic Ethers

Brønsted acid-catalyzed direct C(sp²)-H alkylation of N-heteroaromatics with cyclic ethers via a cross-dehydrogenative coupling reaction in the presence of benzoyl peroxide was developed. This methodology successfully provided an easy access to a variety of alkyl-substituted quinoxaline, benzoimidazole, pyrazine, pyrimidine, quinoline, isoquinoline, and pyridine derivatives in up to 94% yield under metal-free conditions.

Electrochemical dehydrogenative cross-coupling of xanthenes with ketones

An oxidant-free electrochemical dehydrogenative cross-coupling of xanthenes and ketones for the preparation of functionalized 9-alkyl-9H-xanthenes was developed.

Oxidative organocatalysed enantioselective coupling of indoles with aldehydes that forms quaternary carbon stereocentres

The first organocatalysed, metal-free cross-nucleophile coupling of indoles with α-branched aldehydes forming acyclic stereoselective quaternary carbon centres is presented. Applying an amino acid-derived catalyst with suitable organic oxidants affords the desired enantioenriched indole functionalised products with moderate to excellent yield and enantioselectivity. Two metal-free oxidative protocols employing either DDQ or a sequential approach that uses two organocatalysts to facilitate the use of O₂ as the terminal oxidant are disclosed. These methods are compatible with various indoles ranging from electron-rich to -deficient substituents at the C-2, -5, -6, and -7-positions reacting with a series of different α-branched aldehydes.

Tandem sp3 C-H functionlization/decarboxylation of 2-alkylazaarenes with coumarin-3-carboxylic acids

The catalyst-free sp(3) C-H functionalization of 2-alkylazaarenes has been achieved in the reaction with (thio)coumarin-3-carboxylic acids. Followed by a tandem decarboxylation, this method provides facile synthesis of biologically important azaarene-substituted 3,4-dihydro(thio)coumarins in a single step in high yields.

Facile synthesis of azaarene-2-substituted chromanone derivatives via tandem sp3 C–H functionalization/decarboxylation of azaarenes with 4-oxo-4H-chromene-3-carboxylic acid

A facile catalyst-free tandem sp³ C–H functionalization/decarboxylation of 4-oxo-4H-chromene-3-carboxylic acid with 2-alkylazaarenes was developed, which can construct the biologically significant azaarene 2-substituted chromanones in a single step.