Carbon materials like activated carbon (AC) undergo chemisorption with O to give species with electron deficiency in the carbon skeleton and negative charge at the oxygen end that upon reaction with PPh and benzoic acid afford PhP═O. Whereas amine donors react with O-chemisorbed AC and nucleophiles to give dehydrogenatively coupled products in 67-89% yields via the corresponding radical cation and iminium ion intermediates, the reactions using β-naphthoxide derivatives give the corresponding oxidatively coupled bi-2-naphthol products in 68-95% yields.

An efficient protocol for base‐catalysed (4+2) annulation between 2‐nitrobenzofuran and N‐alkoxyacrylamide was developed. The corresponding 1‐alkoxy‐3,4‐dihydrobenzofuro[3,2‐b]pyridin‐2(1H)‐ones were obtained in high to excellent yields by organic base catalysis. In addition, a dearomative nitrotetrahydrobenzofuro[3,2‐b]pyridin‐2(3H)‐ones were also obtained in high yields in the presence of an inorganic base. The advantages of this methodology include easily accessible starting materials, simple operational procedures, broad substrate scope, and synthetically useful yields at milder reaction conditions.

An asymmetric organocatalytic aza-Friedel-Crafts reaction was developed to give the enantioenriched Δ 4 -isoxazoline scaffold bearing a quaternary-substituted stereogenic centre in goodto-excellent yields and enantioselectivity (50-99%, 55-> 99% ee). This protocol involves the in situ generated isoxazolium ions in the presence of a chiral phosphoric acid followed by the heteroarene addition through asymmetric counteranion-directed catalysis.

Enantioselective organocatalytic protocols for the functionalization of electron-deficient internal alkynes and enynes are reviewed. This review focuses on the applicability of activated conjugated π-systems in asymmetric synthesis for providing diversified chiral entities under metal-free reaction conditions. Various organocatalytic strategies with different catalytic modes are demonstrated.