Chiralpak as h

The enantiomeric ratio (er) of the products was
determined by high-performance liquid chromatography on a chiral stationary
phase in a Waters 2695 chromatograph coupled to a Waters 2998 photodiode
array detector. Daicel Chiralpak AS-H and Chiralcel OD-3 and IA columns
(0.46 cm × 25 cm) were used; specific conditions are indicated
for each case.

The analytical columns, CHIRALPAK® AS‐H, IA, IB, IB N‐5, IC, ID, IE, IF, IG, IH, IJ, IK, and CHIRALCEL® OJ‐H sized 4.6 mm I.D. × 250 mm L, were used as brand‐new columns from the Daicel Corporation (Tokyo, Japan). Figure 1 shows their chemical structures of chiral selectors in them. All amylose and cellulose derivatives are chemically immobilized on 5 μm silica particle. Eluents for liquid chromatography were prepared from HPLC‐grade solvents. n‐Hexane (n‐Hex), 2‐propanol (IPA), ethyl acetate (EtOAc), dimethylformamide (DMF), and tetrahydrofuran (THF) were purchased from Fujifilm Wako Pure Chemical (Osaka, Japan). Diethylamine (DEA) was purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan). Ethanol (EtOH), trifluoroacetic acid (TFA), and dichloromethane (DCM) were purchased from Nacalai Tesque (Kyoto, Japan). 1,3,5‐tri‐tert‐butylbenzene (TTB), the void volume marker, was purchased from Sigma‐Aldrich Japan (Tokyo, Japan). Tested racemic compounds were purchased from Fujifilm Wako Pure Chemical (Osaka, Japan) and some tested racemic compounds were kindly supplied from several researchers in academia (see Acknowledgement). Structures of the tested compounds are shown in Figure S1.