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3-Aryl-4-aminomaleimides have well-demonstrated applications, such as being used as fluorophores and inhibitors. However, their previous synthesis methods have involved tedious multi-step procedures or methods that need pre-functionalized maleimides and toxic or unstable reagents. Here, a feasible method is developed to synthesize these useful compounds. This includes the one-pot preparation of 3-aminomaleimides, followed by their direct arylation through a palladium-catalyzed Heck reaction with various aryl iodides regioselectively at the β-position of their amine substituents. The results show that this method efficiently exhibits a broad scope.

A palladium (II)-catalyzed borono- ortho -CH activation/amination cascade for the construction of two C-N bonds and one C-C bond in a single synthetic sequence is reported. This method proceeds through a formal syn -carbopalladation of alkynes with organoboron compounds, forming alkenyl palladium species, which are trapped by simple amines to provide highly substituted indoles. Remarkably, with an electron-rich arylboronic acid, the reaction proceeds through an unexpected anti -carbopalladation terminated by ortho -CH activation of diarylalkyne/amination reaction to provide an unsymmetrically substituted 2,3-diaryl indole instead. In the follow-up chemistry, we demonstrate that urea participates in this cascade to offer a variety of free NH-indoles.

A novel and efficient metal-free C-H functionalization of enynals is developed to synthesize α-pyrone derivatives via the formation of two C-O bonds. In this project, K 2 S 2 O 8 has been introduced as an efficient oxygen source and C-H functionalization agent in regioselective oxidative cyclization reaction with a relatively broad substrate scope.

A regioselective direct alkylation of coumarins at C-3 via cross-dehydrogenative coupling of unactivated Csp2-Csp3 bonds is developed. This protocol employs tert-butyl hydroperoxide as the sole reagent of the reaction to combine coumarins and ethers in reasonable yields under metal- and solvent-free reaction conditions. This protocol also worked well with coumarin-3-carboxylic acids to unveil a rare instance of a catalyst-free tandem alkylation/decarboxylation reaction with conservation of the double bond.

A highly regioselective and transition-metal free one-pot arylation of chromenones with arylboronic acids has been achieved employing K 2 S 2 O 8 . The procedure consists of a sequence of some reactions including an arylation/decarboxylation cascade and proceeds well in aqueous media to afford biologically interesting flavones and 3-arylcoumarins. This method exhibited excellent selectivity and functional group tolerance under mild conditions. The reaction also showed perfect efficacy for the preparation of styryl coumarins.

An approach to synthesize 2,3-diaryl benzo[b]furans using coumarins and aryl bromides is developed. This state-of-the-art strategy capitalizes on a palladium-catalyzed one-pot decarbonylative diarylation of coumarins, paving the way to achieve biologically interesting 2,3-diaryl benzo[b]furans.

A Catellani reaction terminated by palladacycle amination leading to methanocarbazoles is reported. The outcome is the formation of three different Csp(3)-Csp(2)/Csp(3)-N/Csp(2)-N bonds through a Heck reaction/C-H activation/double amination cascade in one process.

A new regioselective α-arylation of coumarins with unactivated simple arenes via a palladium-catalyzed twofold C-H functionalization is devised. This method offers an attractive new approach to synthesis of a wide variety of 3-arylcoumarins from readily accessible starting materials.

A straightforward and atom-economical base-free palladium-catalyzed regioselective direct arylation of coumarins and chromenones is devised. This protocol is compatible with a wide variety of electron-donating and -withdrawing substituents and allows construction of various biologically important flavone and neoflavone backbones.