Stereochemistry of acid-catalyzed cleavage of 3-chloro- and 3-bromonortricyclene in deuterated medium. Evidence for edge protonation of nortricyclenes

Cleavage of 3-chloronortricyclene (4c) and 3-bromonortricyclene (4d) occurs faster than solvolysis in D 2 SO 4 –DOAc at 70–75 °C and yields syn-7-, anti-7-, exo-5-, and endo-5-halo-exo-2-norbornyl acetates as products. That the 7-chloroacetates comprise 70% of the reaction mixture, that 30% of the 5-chloro-exo-2-norbornyl acetates which comprised 28% of the reaction mixture are derived via rearrangement of the syn-7- and anti-7-chloronorbornyl …