79:21). To pivot away from geminal-substitution unsymmetrically substituted cyclopropanes were explored within the framework of this salen photocatalysis platform (Fig. ). It was tempting to speculate that a photostationary composition consisting of a mixture of enantioenriched diastereomers could be reached through a formal kinetic resolution process. Indeed, irradiation of (1.5 eq.) in acetone (4.5 mL) under an argon atmosphere. The reaction mixture was irradiated (400 nm) at -70 °C for 6 h using a quartz-glass rod as an optical guiding rod. Yields are reported based on isolated material, the e.r. was determined by high-performance liquid chromatography (HPLC) analysis on a chiral stationary phase. (B) A formal kinetic resolution of unsymmetrically substituted cyclopropyl ketones. Reactions performed using cyclopropyl ketones (0.30 mmol), Al-1 (10 mol%), 3 Å mol sieves (45 mg) and n-Bu4NCl (1.5 eq.) in acetone (4.5 mL) under an argon atmosphere. The reaction mixture was irradiated (400 nm) at -70 °C using a quartz-glass rod as an optical guiding rod. Yields are reported based on isolated material, the e.r. was determined by high-performance liquid chromatography (HPLC) analysis on a chiral stationary phase. Consistent with a photocatalytic transformation, the deracemization was completely suppressed in the absence of the Al-salen or light: this enabled cyclopropane rac-1 to be recovered quantitatively (Fig. ). Furthermore, omitting molecular sieves compromised reaction efficiency, highlighting the detrimental effect of water on the process. We then turned our attention to the feasibility of the charge-transfer process that is implicit in the mechanism (Fig. ). An electron transfer from the excited state catalyst (E1/2(*PC/PC + ) ≈ -1.47 V vs. SCE) to substrate rac-1 (E1/2 = -1.96 V vs. SCE) would be formally endergonic, yet conceivable under Lewis acid activation of the substrate. Confidence in the feasibility of a straightforward SET process, was addressed in a theoretical study based on DFT (vide infra). Additional confidence in the mechanistic framework stemmed from the study of probes that established the requirement for radical stabilizing substituents; e.g. aryl or carbonyl on the cyclopropane, to facilitate rapid ringopening which is a pre-condition for deracemization. However, di-ethyl substituted cyclopropane 19 proved to be unreactive under the standard reaction conditions, and racemic material was reisolated (95% yield). In addition, replacement of the aryl ketone by a methyl ester (20) was unsuccessful and, again, led to the recovery of racemic starting material: this is likely due to a significantly increased reduction potential of the ester group compared to the aryl ketone motif.