CYCLODIMERIZATION OF BICYCLO[2.2.1]HEPTA-2,5-DIENE BY RHODIUM CARBOXYLATES

It is shown that the adduct of Rh//2(CF//3COO)//4 with NBD is formed in dichloromethane at room temperature. The addition of an NBD excess to the Rh//2(CF//3COO)//4 solution results in the reduction of Rh(II) to Rh(I). Heating of Rh//2(CF//3COO)//4 either in NBD or in its mixture with benzene (1:3) yields red crystals of left bracket Rh(NBD)CF//3COO right bracket //2. This compound is the catalyst of NBD cyclodimerization. The selectivity of cyclodimer formation is regulated by the ligand environment of the rhodium atom.