The synthetic potential of the Bergman cyclization (BC)[1] has not been greatly explored despite remarkable progress in the understanding of the reaction mechanism [2] and the mode of biological action of enediynes.[3] The radicals within the 1, 4-diradical generated during the BC are distally oriented, thus preventing self-quenching, which can lead to a highly strained bicyclo system, and are spinpaired by an external quencher.[4] The 1, 4- ...