Acid-catalyzed Ring Opening of Halo-nortricyclanes

The acid-catalyzed (CH 3 COOH–0.1 M H 2 SO 4 ) opening of the cyclopropyl ring in nortricyclyl chloride and nortricyclyl bromide gives in each case the anti-7-, syn-7-, exo-5-, and endo-5-halo-exo-2-norbornyl acetates as the major products. When the reactions are carried out in deuterated medium the deuterium is situated endo at C-6 in the anti- and syn-7- haloacetates and establishes that at least 75% of the products arise from …