Visible-Light-Promoted Aryl Cation Formation: Aromatic SN1 Reactions of Areneazo-2-(2-nitro)propanes.

The visible light excitation of areneazo-2-(2-nitro)propane·HCl salts generated the singlet aryl cation that readily underwent aromatic SN1 reactions with a variety of nucleophiles. The in situ generated singlet aryl cation was stabilized by a counter nitronate anion that prevented other intersystem crossing and single electron transfer processes. With the improved safety features of neutral areneazo-2-(2-nitro)propane derivatives, the current visible-light-promoted aromatic SN1 reactions provide an alternative aryl Csp2-X bond forming strategy.

Catalytic Aerobic N-Nitrosation by Secondary Nitroalkanes in Water: A Tandem Diazotization of Aryl Amines and Azo Coupling.

Secondary nitroalkanes underwent oxygen-mediated nitro-nitrite isomerization, serving as versatile N-nitrosating agents under aerobic conditions. To capitalize on the newly discovered aerobic nitro-nitrite isomerization phenomenon, a phase-transfer catalysis system employing KSeCN and TBAI was developed, in which the tandem diazotization and azo coupling with nitroalkanes as well as N-nitrosation of amines were accomplished. The current tandem diazotization and azo coupling strategy provides a facile synthesis of areneazo-2-(2-nitro)propane derivatives, a safe synthetic alternative to aryl diazonium salts.

Palladium mediated domino reaction: synthesis of isochromenes under aqueous medium.

Isochromenes have been synthesized using palladium-catalyzed C-C and C-O bond forming reactions starting from ortho-bromo tertiary benzylic alcohols and internal acetylenes. Notably, this domino process is feasible by using the green solvent, water. The protocol exhibited a broad substrate scope and afforded various isochromenes.

A Domino Palladium-Catalyzed Cyclization: One-Pot Synthesis of 4b-Alkyl-10-phenyl-4b,5-dihydroindeno[2,1-a]indenes via Carbopalladation Followed by C-H Activation.

An effective domino one-pot [Pd]-catalysis for the construction of novel tetracyclic compounds was described. This process involved in the construction of three C-C bonds from simple and readily available 1-bromo-2-isopropenylbenzenes and internal alkynes. A variety of fused tetracyclic dihydroindeno-indenes were accomplished.