Facile and Efficient Bromination of Benz[F]Indan-1-One

Abstract

The bromination reaction of benz[f]indan-1-one was investigated by NBS, molecular bromine and fotobromination. Benz[f]indan-1-one was synthesized by treatment of α,α,α',α'tetrabromo-o-xylene with cyclopenten-1-one. Bromination of benz[f]indan-1-one with bromine (1.2 equiv) at low temperature afforded the α-monobromobenz[f]indanone in addition to α,α'dibromobenz[f]indanone. The quantitative yield of α,α'-dibromobenz[f]indanone was synthesized by treatment of benz[f]indan-1-one with 2.1 equv. bromine at room temperature for 25 min. The electrophonic bromination of α,α'-dibromobenz[f]indanone with N-bromosuccinimide (NBS) regioselectively proceeded at C-8 side and afforded the corresponding 2,2,8Tribromobenz[f]indanone which also could be obtained from the treatment of benz[f]indan-1-one with NBS and SiO₂. Dibromobenz[f]indenone was generated by the treatment of benz[f]indan-1-one with bromine in photochemical reaction apparatus irradiated by 150 watt projection lamp. Dibromobenz[f]indenone was also synthesized by the treatment of α,α'-dibromobenz[f]indanone with NBS in photochemical reaction apparatus irradiated by 150 watt projection lamp. 2,8Dibromobenz[f]indanone was synthesized by the reaction of α-monobromobenz[f]indanone with NBS.