Reacts via ene insertion reactions into σ bonds. Prepn: H. W. Moore, W. Weyler, Jr., J. Am. Chem. Soc. 92, 4132 (1970). Reaction with cyclopropanes: M. D. Gheorghiu et al., J. Org. Chem. 55, 3713 (1990). Cycloaddition reactions with vinylarenes: S. V. Sereda et al., Struct. Chem. 4, 333 (1993); M. D. Gheorghiu et al., Rev. Roum. Chim. 40, 653 (1995).