Hetero-Diels-Alder approach to Bis(indolyl)methanes.

A novel synthetic approach to bis(indolyl)methanes has been established. Our one-pot synthetic strategy based on two consecutive hetero-Diels-Alder cycloaddition reactions of electrophilic conjugated nitrosoalkenes with indoles was extended to a range of new 1-hydroxyiminomethyl-bis(indolyl)methanes. Furthermore, a similar and broad range approach was applied to the synthesis of previously unknown 1-hydrazonomethyl-bis(indolyl)methanes. The biological evaluation of the new bis(indolyl)methanes as anti-cancer agents was investigated.