A versatile and broad range approach to previously unknown bis(indolyl)methane oximes based on two
consecutive hetero DielseAlder cycloaddition reactions of electrophilic conjugated nitrosoalkenes with
indoles is disclosed. The cytotoxic properties and selectivity of some adducts against several human
cancer cell lines pointing to a promising role in the development of anti-tumoural drugs, in particular for
leukaemia and lymphoma.