The thermal reaction of enyne-allenes 1 with large substituents (tert.-butyl, trimethylsilyl) at the acetylene terminus leads to C2C6 cyclization products presumably via an intermediate benzofulvene biradical, whereas with a hydrogen substituent the expected Myers-Saito cycloaromatization product is formed. Effective DNAstrand scission can be observed when no intramolecular pathway is available.