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combined, washed with brine, dried over anhydrous MgSO4, and evaporated. The residue was purified
by flash column chromatography on silica gel with a 20:1 mixture of CHCl3 and MeOH to give the
pure 6 (214 mg, 90%) as a colorless powder. Mp = 134–136 °C; [α]2D0 = +7.9° (c = 1.01 in MeOH);
1H-NMR (500 MHz, CD3OD): δ = 1.01 (d, J = 6.9 Hz, 3H), 1.02 (d, J = 6.9 Hz, 3H), 1.90–1.97
(m, 1H), 2.82–2.86 (m, 1H), 3.14 (dd, J = 8.6, 13.1 Hz, 1H), 3.41 (dd, J = 3.5, 13.1 Hz, 1H); 13C-NMR
(125 MHz, CD3OD): δ = 18.9, 19.0, 30.1, 47.4, 60.7, 110.2–120.4 (complex signals of –CF2 and
–CF3); Anal. Calcd for C9H13F9N2O2S: C, 28.13; H, 3.41; N, 7.29. Found: C, 28.07; H, 3.39; N, 7.26.
3.3. Preparation of Organocatalyst 7
(S)-tert-Butyl 3-methyl-1-(perfluorooctanesulfonamido)butan-2-ylcarbamate (10). To a solution of
(S)-tert-butyl 1-amino-3-methylbutan-2-ylcarbamate (8) [50] (385 mg, 1.90 mmol) in dry CH2Cl2 (20 mL)
was added triethylamine (0.80 mL, 5.71 mmol) at room temperature under an argon atmosphere. After
stirring for 5 min, perfluorooctanesulfonyl fluoride (1.57 mL, 5.71 mmol) was added to the reaction
mixture at 0 °C. After stirring for 2 h at 0 °C, the reaction mixture was additionally stirred for 90 h at
room temperature. The reaction mixture was added to water and extracted three times with EtOAc.
The EtOAc layers were combined, washed with brine, dried over anhydrous MgSO4, and evaporated.
The residue was purified by flash column chromatography on silica gel with a 6:1 mixture of hexane
and EtOAc to give the pure 10 (602 mg, 46%) as a pale yellow oil. [α]2D4 = −4.2° (c = 1.28 in MeOH);
1H-NMR (500 MHz, CDCl3): δ = 0.95 (d, J = 7.4 Hz, 3H), 0.97 (d, J = 6.8 Hz, 3H), 1.44 (s, 9H),
1.80–1.85 (m, 1H), 3.25 (m, 1H), 3.46 (brd, J = 12.6 Hz, 1H), 3.55 (m, 1H), 4.67 (brd, J = 8.0 Hz, 1H),
7.13 (brs, 1H); 13C-NMR (125 MHz, CDCl3): δ = 18.0, 19.2, 28.2, 30.1, 48.4, 55.7, 80.8, 108.0–113.0
(complex signals of –CF2 and –CF3), 157.6; HRMS (ESI-TOF): calcd for C18H21F17N2O4SNa
(M+Na)+: 707.0848, Found: 707.0873.
(S)-N-(2-Amino-3-methylbutyl)-perfluorooctanesulfonamide (7). To a solution of 10 (570 mg, 0.833 mmol)
in EtOAc (3.5 mL) was added a 4M solution of hydrochloric acid in EtOAc (3.5 mL) at 0 °C.
After stirring for 2 h at room temperature, the reaction mixture was evaporated. The residue was added
to saturated aqueous NaHCO3 and extracted three times with EtOAc. The EtOAc layers were
combined, washed with brine, dried over anhydrous MgSO4, and evaporated. The residue was purified
by flash column chromatography on silica gel with a 20:1 mixture of CHCl3 and MeOH to give the
pure 7 (444 mg, 91%) as a colorless powder. Mp = 144–145 °C; [α]2D4 = + 6.9° (c = 1.01 in MeOH);
1H-NMR (500 MHz, CD3OD): δ = 1.01 (d, J = 6.8 Hz, 3H), 1.03 (d, J = 6.8 Hz, 3H), 1.90–1.97 (m,
13
1H), 2.82–2.86 (m, 1H), 3.15 (dd, J = 8.5, 13.1 Hz, 1H), 3.41 (dd, J = 4.0, 13.1 Hz, 1H); C-NMR
(125 MHz, CD3OD): δ = 18.9, 19.0, 30.1, 47.5, 60.7, 109.7–121.5 (complex signals of –CF2 and
–CF3); Anal. Calcd for C13H13F17N2O2S: C, 26.72; H, 2.24; N, 4.79. Found: C, 26.75; H, 2.41; N, 4.86.
3.4. Typical Procedure for Michael Addition (Table 3)
A typical procedure of the Michael additions using 6 is as follows: To a solution of 11 (30.8 mg,
0.100 mmol) and organocatalyst 6 (3.8 mg, 0.010 mmol) in m-xylene (1.0 mL) was added
2-phenylpropanal (26.8 µL, 0.200 mmol) and trifluororacetic acid (0.7 µL, 0.010 mmol) at room
temperature. After stirring at room temperature for 2 h, the reaction mixture was directly purified by