Catalytic asymmetric Friedel-Crafts alkylation of unprotected indoles with nitroalkenes using a novel chiral Yb(OTf)-pybox complex.

Chiral chloro-indeno pybox has served as a new ligand for the Yb(OTf)-catalyzed asymmetric Friedel-Crafts alkylation reaction of indoles with nitroalkenes. The tunable nature of pybox ligands enables the rational design of catalysts for optimal performance in terms of both activity and stereoselectivity in a Friedel-Crafts-type reaction. Good to excellent yields and enantioselectivities were obtained for a relatively wide range of substrates, including sterically hindered compounds, under optimized reaction conditions.

One-pot, three-component synthesis of spirooxindoles catalyzed by ZnO nano-rods in solvent-free conditions.

Recyclable ZnO nano-rods catalyst as a most efficient and straightforward protocol for one-pot, three-component synthesis of spirooxindole derivatives at room temperature under solvent-free conditions in both reaction media and work-up procedure is described. This method is of great value because of its environmentally benign character, easy handling, high yields, convenient operation (grinding), room temperature, low cost and green.