Herein, we report an efficient synthesis of azaspiro[4,5]‐decanes and azaspiro[4,5]‐trienones by the radical cascade spirocyclization of N‐benzylacrylamides or N‐arylpropiolamides respectively. These reactions proceed under metal free conditions and involve in situ generation of aryl sulfonyl radicals from DABSO and aryl diazonium salts. Furthermore, a catalyst free visible light mediated protocol was developed for the sulfonylative spirocyclization of N‐aryl alkynamides using diaryliodonium salts. The utility of these protocols were justified by the excellent compatability of a wide range of functional groups, good yields and scalablity under mild conditions at room temperature.

An efficient Cp*CoIII‐catalyzed C8‐dienylation of quinoline‐N‐oxides was achieved by employing allenes bearing leaving groups at the α‐position as the dienylating agents. The reaction proceeds by CoIII‐catalyzed C−H activation of quinoline‐N‐oxides and regioselective migratory insertion of the allene followed by a β‐oxy elimination, leading to overall dienylation. Site‐selective C−H activation was achieved with excellent selectivity under mild reaction conditions, and 30 mol % of a NaF additive was found to be crucial for the efficient dienylation. The methodology features high stereoselectivity, mild reaction conditions, and good functional‐group tolerance. C8‐alkenylation of quinoline‐N‐oxides was achieved in the case of allenes devoid of leaving groups as coupling partners. Furthermore, gram‐scale preparation and preliminary mechanistic experiments were carried out to gain insights into the reaction mechanism.

The catalytic alkenylation of the unactivated distal γC(sp)-H bonds of aliphatic acids with simple acrylates and vinyl iodides is described. This method allows for the introduction of an alkene group into aliphatic acid derivatives in the form of activated olefins and vinyl iodides. Notably, olefination with vinyl iodides provides access to a wide range of challenging γ-vinyl acid derivatives with aliphatic olefin functionality introduced in a diastereoselective manner.

Herein, we report a copper-catalyzed novel, highly efficient, and modular cascade annulation reaction for the synthesis of quinoline derivatives starting from easily available alkynes, isothiocyanates, and diaryliodonium salts. The reaction displayed excellent regioselectivities, when unsymmetrical alkynes were employed as partners, giving access to diversely functionalized quinolines in good to excellent yields for a wide range of functional groups.