The concise, enantioselective total syntheses of (-)-citrinadin A and (+)-citrinadin B in a total of only 20 and 21 steps, respectively, from commercially available starting materials are described. Our strategy, which minimizes refunctionalization and protection/deprotection operations, features the highly diastereoselective, vinylogous Mannich addition of a dienolate to a chiral pyridinium sa...

A synergetic effect of ultrasonic irradiation and yolk–shell nanocatalyst was examined for the synthesis spirooxindoles from isatin, malononitrile cyclohexanone. It found this contributory can be accelerated desired reaction toward obtaining highly pure products in excellent yields short times. The contains melamine anchored onto magnetic Fe3O4 nanoparticles were applied as active base catalyst...

a simple and efficient one-pot three-component synthesis of the biologically important spirooxindole-4h-pyrans was carried out by the reaction of isatin, activated methylene reagents, and 4-hydroxycoumarin in aqueous medium. sba-pr-nh2 was found to be an efficient heterogeneous nanoporous solid basic catalyst (pore size of 6 nm) which can be easily handled and removed from the reaction mixture ...

Single-step constructions of molecules with multiple quaternary carbon stereocentres are rare. The spirooxindole structural motif is common to a range of bioactive compounds; however, asymmetric synthesis of this motif is complicated due to the presence of multiple chiral centres. The development of organocatalytic cascade reactions has proven to be valuable for the construction of several chir...