entrya catalyst solvent hydrogen donor yield (%) ee (%)
1 Cat1 DCM HCO2H/Et3N (5:2) <5
2 Cat2 DCM HCO2H/Et3N (5:2) <5
3 Cat3 DCM HCO2H/Et3N (5:2) 99 98
4 Cat4 DCM HCO2H/Et3N (5:2) 40 98
5 Cat5 DCM HCO2H/Et3N (5:2) <5
6 Cat6 DCM HCO2H/Et3N (5:2) 99 >99
7b Cat6 THF HCO2H/Et3N (5:2) 57 >99
8b Cat6 DCM HCO2H/Et3N (5:2) 35 99
9b Cat6 toluene HCO2H/Et3N (5:2) 56 99
10b Cat6 MeCN HCO2H/Et3N (5:2) 54 99
11b Cat6 MeOH HCO2H/Et3N (5:2) 12 99
11b Cat6 iPrOH HCO2H/Et3N (5:2) 25 >99
12b Cat6 THF HCO2H/Et3N (3:2) 85 >99
13b Cat6 THF HCO2H/Et3N (1:1) 96 >99
14b Cat6 THF HCO2H/DBU (1:1) 99 >99
15b Cat6 THF HCO2H/DIPEA (1:1) 94 >99
16b Cat6 THF HCO2Na 17 >99
17b Cat6 THF IPA <5
18c Cat6 THF HCO2H/DBU (1:1) 98 >99
19d Cat6 THF HCO2H/DBU (1:1) 65 >99