Bergman cyclization

These compounds generate the diradical intermediate described above which can cause single and double stranded DNA cuts.

[5] A biradical mechanism is also proposed for the formation of certain biomolecules found in marine sporolides that have a chlorobenzene unit as part of their structure.

A model reaction with the enediyene cyclodeca-1,5-diyn-3-ene, lithium bromide as halogen source and acetic acid as hydrogen source in DMSO at 37 °C supports the theory:[6][7] The reaction is found to be first-order in enediyne with the formation of p-benzyne A as the rate-limiting step.

The anion is a powerful base, stripping protons even from DMSO to final product.

In 2015 IBM scientists demonstrated that a reversible Masamune-Bergman cyclisation of diyne can be induced by a tip of an atomic force microscope (AFM).