Naphthalene, cycloaddition reactions reduction

Reduction of NHC-borane adducts has proven useful for purposes other than the synthesis of boron-boron multiple bonds. Bissinger et al. [124] successfully employed this technique to prepare a trapped form of borylene, BH. NHC-stabi-lized dichloroborane (IMe-BHCl2) was prepared from BHCl2 SMe2 and then subsequentiy dehalogenated with 2 equivalents of sodium naphthalenide (NaN), yielding the naphthalene-trapped IMe BH adduct (Scheme 15.10). The authors propose that this reaction occurs via a [2+1] cycloaddition pathway and provide quantum chemical calculations to support this notion. 

---