An Effective Regioselective Electrophilic Halogenation of Tricyclo[5.2.1.02,6]decenyl Enaminones.

Abstract 5-Amino- endo -tricyclo[5.2.1.0 2,6 ]deca-4,8-dien-3-ones 4 undergo a surprisingly effective regioselective halogenation using N-halosuccinimides (NXS) under electrophilic conditions. Exclusive α-halogenation is observed using one equiv. of NXS, whereas, either α,γ- or α,N-bishalogenation products are formed in quantitative yields when an additional equiv. of NXS is applied. Most importantly, halogenation of the C 8 C 9 norbornene bond is not observed.