In mixed [2 + 2] photoadditions with the chiral auxiliary in either the enone or the alkene component, it was found that changing the polarity of the solvent or the temperature of the irradiation had a marked effect on the extent of asymmetric induction. © 1987.
Lange, G. L., Decicco, C., & Lee, M. (1987). Asymmetric induction in mixed [2 + 2] photoadditions. Effect of solvent, alkene concentration and temperature. Tetrahedron Letters, 28(25), 2833–2836. https://doi.org/10.1016/S0040-4039(00)96221-X