A series of complexes of the form TpRe(CO)(L)(eta(2)-naphthalene) (Tp = hydridotris(pyrazolyl)borate) undergoes tandem electrophile/nucleophile addition reactions with a high degree of regiocontrol depending on the auxiliary ligand, L. When L = PMe3, the reaction of the eta(2)-naphthalene complex with triflic acid followed by a silyl ketene acetal favors the 1,4-addition product, whereas when L = pyridine, N,N-dimethylaminopyridine, N-methylimidazole, or NH3 the 1,2-addition product is favored. These reactions proceed with excellent stereocontrol: both electrophile (H+, D+) and nucleophile (silyl ketene acetal) add anti to the face of metal coordination, and a single coordination diastereomer can be isolated for each reaction. one-electron oxidation of the Re complex affords the corresponding free dihydronaphthalene in good yield.