Hassen Boudebous, Berta Kosmrlj, Boris Sket and Jakob Wirz, "Primary Photoreactions of the 3',5'-Dimethoxybenzoin Cage and Determination of the Release Rate in Polar Media", J. Phys. Chem. A 2007, 111, 2811-2813.
Abstract: Picosecond pump-probe spectroscopy of 3',5'-dimethoxybenzoin fluoride and acetate revealed that cyclization of the of singlet excited state to a preoxetane biradical is the dominant primary photochemical step. The release rate in on the order of 1E9 s-1 in polar solvents.