Four- and Sixfold Tandem-Domino Reactions Leading to Dimeric Tetrasubstituted Alkenes Suitable as Molecular Switches.

A highly efficient palladium-catalyzed fourfold tandem-domino reaction consisting of two carbopalladation and two C-H-activation steps was developed for the synthesis of two types of tetrasubstituted alkenes 3 and 6 with intrinsic helical chirality starting from substrates 1 and 4, respectively. A sixfold tandem-domino reaction was also developed by including a Sonogashira reaction. 20 compounds with different substitution patterns were prepared with yields of up to 97 %.

A fast way to fluorescence: a fourfold domino reaction to condensed polycyclic compounds.

A fast and efficient palladium-catalyzed fourfold domino Sonogashira/double-carbopalladation/CH-activation reaction that converts simple aromatic systems into complex polycyclic hydrocarbons has been developed. A number of substituted products has thus been prepared in yields up to 89 %. The structural assignment has been confirmed by using single-crystal X-ray crystallography.