L-proline in acetonitrile T=0°C; 8 h;

1: With diisobutylaluminium hydride in dichloromethane T=-78 - -70°C; 2 h; 2: With methanol in dichloromethane T=-70 - 20°C;

Hua Cat in dichloromethane T=20°C; Mannich reaction; 13 h; optical yield given as percent eeenantioselective reaction;

potassium fluoride; L-proline in chloroform T=20°C; Mannich type addition; 16 h; optical yield given as percent deenantioselective reaction;

1: propionaldehyde With (S)-[α,α-bis(3,5-bistrifluoromethyl)phenyl]-2-pyrrolidine methanol trimethylsilyl ether in chloroform T=30°C; 0.0833333 h; 2: N-tert-butyloxycarbonyl-α-(phenylsulfonyl)benzylamine With potassium fluoride in chloroform T=30°C; Mannich reaction; 96 h; optical yield given as percent eeenantioselective reaction;

1: propionaldehyde With 5-[(2S)-pyrrolidine-2-yl]-1H-tetrazole in chloroform T=20°C; 0.0833333 h; 2: N-[phenyl(toluene-4-sulfonyl)methyl]tert-butoxycarboxyamide With potassium fluoride in chloroform T=20°C; Mannich reaction; 24 h; optical yield given as percent eeenantioselective reaction;

1: formic acid / tetrahydrofuran; water / 18 h / 20 °C / Inert atmosphere 2: potassium carbonate / tetrahydrofuran / 15 h / 80 - 85 °C / Inert atmosphere; Reflux 3: L-proline / acetonitrile / 12 h / 0 °C / Inert atmosphere View Scheme

1: formic acid / tetrahydrofuran; water / 18 h / 20 °C / Inert atmosphere 2: potassium carbonate / tetrahydrofuran / 15 h / 80 - 85 °C / Inert atmosphere; Reflux 3: L-proline / acetonitrile / 12 h / 0 °C / Inert atmosphere View Scheme

1: caesium carbonate / tetrahydrofuran / 3 h / 50 °C 2: L-proline / acetonitrile / 18 h / 0 °C View Scheme

(3S,4S)-3-(tert-butyldimethylsilyloxy)-4-(trifluoromethylsulfonamido)pyrrolidine T=20°C; 44 h;