DABCO-mediated isocyanide-based multicomponent reaction: synthesis of highly substituted cyclopentenes.

Highly substituted cyclopentenes can be accessed rapidly from isocyanides, aldehydes and malononitrile or ethyl cyanoacetate (AB2C2) using DABCO as a catalyst under solvent-free conditions at 40 °C within 30 min.

Three-component cascade annulation of ß-ketothioamides promoted by CF3CH2OH: a regioselective synthesis of tetrasubstituted thiophenes.

A rapid and highly efficient method for the regioselective synthesis of thiophene derivatives has been developed by annulation of ß-ketothioamides with arylglyoxals and 5,5-dimethyl-1,3-cyclohexanedione in CF3CH2OH within 15 min. The present synthesis has several desirable features, such as high regioselectivity, a concise one-pot protocol, short reaction time, and easy purification. This methodology provides an alternative approach for easy access to tetrasubstituted thiophenes via a one-pot cascade reaction without other additives.