Photosensitized Enantiodifferentiating Polar Addition of Alcohols to 1,1-Diphenylpropene in Supercritical Fluids

Abstract

We have recently reported the first enantiodifferentiating isomerization of (Z)-cyclooctene in supercritical carbon dioxide (scCO₂). The critical control of the enantiomeric excess (ee) of chiral product was achieved through a small change of pressure particularly in the low-density region near the critical density. In this study, the photochemical enantiodifferentiating addition of alcohols to 1,1-diphenylpropene sensitized by chiral naphthalenepolycarboxylates was performed in supercritical carbon dioxide for the first time to investigate the effects of solvation and so-called "clustering effect" upon bimolecular asymmetric photoreaction. The critical control of product ee and even the switching of product chirality were observed by changing the reaction media from homogeneous solvent to scCO₂ with an appropriate sensitizer.