Highly efficient photoinduced rearrangement of benzobicyclo[3.1.0]hexenones to 1-naphthols

Irradiation of 1-(o-tolyl)-3,4-benzobicyclo[3.1.0]hexenones (1) in benzene at 365 nm has resulted in clean conversion to 3-(o-tolyl)-1-naphthols (2) via 3-(o-tolyl)-1(2H)-naphthalenones. The reaction is suggested to occur mainly from (n, π*)3 state with a reaction rate higher than 1010 s−1.