Pd-catalyzed directing-group-assisted regioselective halogenations to C7 of indolines and C8 of tetrahydroquinolines were achieved in good to excellent yields. The practicality and utility of the developed method have been illustrated by various functional group transformations such as arylation, alkenylation, cyanation, and silylation utilizing the installed synthetic handle. The concise synthesis of primaquine, an antimalarial drug, and formal syntheses of two bioactive natural products, hippadine and pratosine, have also been demonstrated.

A metal-free domino multicomponent reaction for the direct CÀ H benzylation and alkylation of quinoxalin-2(1H)-ones using alkenes is described. Triggered by the sulfonyl radical generated from sulfinic acid, the alkenes are transformed to alkyl radicals that react exclusively at the C-3 position of quinoxalin-2(1H)-ones. Importantly, the method not only functionalizes medicinally important quinoxalin-2(1H)-one scaffold, but also furnishes diverse medicinally relevant sulfones in good to excellent yields under mild conditions.

We report a metal-free, oxidant-free, highly regioselective halogenations protocol (chlorination, bromination and iodination) to amidoquinolines using N-halosaccharin derivatives. Various amidoquinolines are tolerated by the method and delivered C5-haloamidoquinoline derivates in excellent yields. A homo and hetero bis-halogenation protocol has also been established. Late stage drug molecule diversification has also been demonstrated using the developed protocol.

A general protocol has been developed for the construction of carbon–heteroatom (C–N, C–Cl, C–O, C–S, and C–Se) bonds using the bench stable, earth-abundant, and environmentally benign copper catalyst. Only oxygen is sufficient to regenerate the copper catalyst. Control experiments suggested that the proto-demetalation step is reversible. Depending on the coupling partner, the reaction follows either disproportionation or radical pathways to complete the catalytic cycle. The synthetic utility of the developed protocol has been demonstrated via various functional group transformations.

A palladium catalyzed directing group assisted cross-coupling of aliphatic aziridines with indole, indoline, tetrahydroquinoline, and aniline has been developed to furnish the corresponding β-arylethylamine derivatives. The substrate scope was very general, and the protocol was also tolerated in the presence of various external additives. Control experiments suggested that the C−H cleavage step is the rate-determining step.