Reductive debromination with activated Ni provides a simple route to o-xylylene, which can be trapped by dienophiles: J. Org. Chem., 53, 339 (1988). o-Xylylene can also be generated using Zn metal and ultrasound: J. Org. Chem., 47, 751 (1982), or NaI in DMF: Chem. Pharm. Bull., 22, 2159 (1974). Dialkylating agent for the formation of a variety of benzo-fused carbocyclic and heterocyclic ring systems, e.g. five-membered with Meldrum’s acid (Isopropyl-idene malonate): Org. Prep. Proced. Int., 24, 185 (1992), 7-membered with Dimethyl- acetone-1,3-dicarboxyl-ate: J. Org. Chem., 54, 5237 (1989), as well as macrocycles and cryptands; see, e.g.: J. Org. Chem., 57, 6112 (1992). Reaction with 1,2- and 1,3-diols has been used a method of protection; the diol can be regenerated by hydrogenolysis: Synth. Commun., 19, 3363 (1989).
