Fig. 3: Scope of substrates regarding various drug derivatized aldehydes.
Reaction conditions were as follows: in the glovebox, CrCl2 (10 mol%) and (S, R)-L1 (12 mol%) were added to a mixture of THF (0.3 mL) and DCE (1.4 mL). The mixture was stirred for 15 min at room temperature and transferred to another vial containing Mes2Acr-tBu2BF4 (PC1, 10 mol%), 1a (0.4 mmol, 2 equiv.), 2a (0.6 mmol, 3 equiv., 2 M in THF, 0.3 mL) and drug derivatized aldehyde 3 (0.2 mmol, 1 equiv.). The final reaction mixture was irradiated with 30 W 450 nm blue LEDs with a cooling fan for 17 h outside under N2. Isolated yields. The ee values were determined by HPLC analysis on a chiral stationary phase.
