An efficient four-component cascade reaction for the synthesis of trisubstituted hexahydroimidazoA C H T U N G T R E N N U N G [1,2-a]pyridines starting from readily available aldehydes, ketones and ethane-1,2diamine catalyzed by p-toluenesulfonic acid is described. Two new cycles and five new bonds are constructed with all reactants being efficiently utilized in this transformation. The mechanism of the reaction was investigated and some crucial reaction intermediates were observed.

The first asymmetric aza-Friedel-Crafts reaction of 2-naphthol with tosylimines was developed via a dinuclear zinc catalyst (up to 98% ee). It provided a new method for the asymmetric synthesis of Betti base derivatives.

A series of polymer-supported chiral b-hydroxy amides and C 2 -symmetric b-hydroxy amides have been synthesized and successfully used for the enantioselective addition of phenylacetylene to aldehydes. High yields (up to 93%) and enantioselectivities (up to 92% ee) were achieved by using polymer-supported chiral bhydroxy amide 4b. The resin 4b is reused four times, giving the product with enantioselectivity 80% ee. Fortunately, it is found that this heterogonous system is suitable not only for aromatic aldehydes but also aliphatic aldehyde.

An efficient microwave-assisted solvent-free synthesis of 3-alkyl-6-aryl[1,2,4]triazolo [3,4-b][1,3,4]thiadiazine derivatives is reported. Twelve derivatives have been synthesised in excellent yields in short reaction times.