2-Oxoimidazolidine-4-carboxylate as a Chiral Auxiliary
J . Org. Chem., Vol. 62, No. 17, 1997 5835
ter t-Bu tyl (4S)-3-[(2R)-3,3-bis(ter t-bu toxyca r bon yl)-2-
m et h ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r -
boxyla te [(S,R)-8d ]: colorless needles, mp 144-145 °C (Et2O/
(9H, s), 1.60-1.85 (2H, m), 2.91 (3H, s), 3.27 (1H, dd, J ) 4.0,
9.6 Hz), 3.62-3.72 (1H, m), 3.73 (6H, s), 3.89 (1H, d, J ) 8.0
Hz), 4.55 (1H, dd, J ) 4.0, 10.1 Hz), 4.71-4.80 (1H, m); IR
(film) 1737, 1680 cm-1; SIMS m/ z 429 (M+ + 1), 373, 229
(base), 169, 99. Anal. Calcd for C20H32N2O8: C, 56.06; H, 7.53;
N, 6.54. Found: C, 55.78; H, 7.79; N, 6.45.
ter t-Bu tyl (4S)-3-[(2R)-3,3-bis(m eth oxyca r bon yl)-2-(2-
p h en yleth yl)-p r op ion yl]-1-m eth yl-2-oxoim id a zolid in e-4-
ca r boxyla te [(S,R)-8h ]: colorless needles, mp 119-120 °C
(Et2O/hexane); [R]24D +4.2 (c 0.50, MeOH); 1H NMR (CDCl3) δ
1.47 (9H, s), 1.79-2.12 (2H, m), 2.54-2.85 (2H, m), 2.90 (3H,
s), 3.30 (1H, dd, J ) 4.5, 9.6 Hz), 3.65-3.75 (1H, m), 3.69 (3H,
s), 3.75 (3H, s), 4.06 (1H, d, J ) 11.0 Hz), 4.69 (1H, dd, J )
4.5, 10.5 Hz), 4.77-4.88 (1H, m), 7.11-7.29 (5H, m); IR (KBr)
1747, 1674 cm-1; SIMS m/ z 477 (M+ + 1), 421, 245, 91 (base).
Anal. Calcd for C24H32N2O8: C, 60.49; H, 6.77; N, 5.88.
Found: C, 60.28; H, 6.86; N, 5.63.
hexane); [R]27 -39.7 (c 1.01, MeOH); 1H NMR (CDCl3) δ 1.24
D
(3H, d, J ) 7.0 Hz), 1.40 (9H, s), 1.45 (9H, s), 1.47 (9H, s),
2.88 (3H, s), 3.29 (1H, dd, J ) 3.8, 9.6 Hz), 3.63-3.74 (2H, m),
4.31-4.48 (1H, m), 4.66 (1H, dd, J ) 3.8, 10.3 Hz); IR (KBr)
1743, 1721, 1681 cm-1; SIMS m/ z 471 (M+ + 1), 415, 359, 303,
145, 99, 57 (base). Anal. Calcd for C23H38N2O8: C, 58.71; H,
8.14; N, 5.95. Found: C, 58.33; H, 7.81, N, 6.00.
ter t-Bu tyl (4S)-3-[(2S)-3,3-bis(ter t-bu toxyca r bon yl)-2-
m et h ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r -
boxyla te [(S,S)-8d ]: colorless needles, mp 114-115 °C (Et2O/
hexane); [R]25 -61.6 (c 1.02, MeOH); 1H NMR (CDCl3) δ 1.18
D
(3H, d, J ) 7.1 Hz), 1.42 (9H, s), 1.46 (18H, s), 2.89 (3H, s),
3.29 (1H, dd, J ) 4.0, 9.5 Hz), 3.61-3.71 (2H, m), 4.35-4.55
(2H, m); IR (KBr) 1745, 1722, 1676 cm-1; SIMS m/ z 471 (M+
+ 1), 415, 359, 303 (base), 145, 99, 57. Anal. Calcd for
C23H38N2O8: C, 58.71; H, 8.14; N, 5.95. Found: C, 58.35; H,
7.82; N, 6.02.
ter t-Bu tyl (4S)-3-[(2S)-3,3-bis(m eth oxyca r bon yl)-2-(2-
p h en yleth yl)-p r op ion yl]-1-m eth yl-2-oxoim id a zolid in e-4-
ca r boxyla te [(S,S)-8h ]: colorless oil; [R]25 -60.3 (c 0.68,
D
ter t-Bu tyl (4S)-3-[(2R)-3,3-bis((ben zyloxy)ca r bon yl)-2-
m et h ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r -
boxyla te [(S,R)-8e]: colorless needles, mp 115-116 °C (Et2O/
1
MeOH); H NMR (CDCl3) δ 1.46 (9H, s), 1.90-2.10 (2H, m),
2.48-2.74 (2H, m), 2.89 (3H, s), 3.23 (1H, dd, J ) 4.1, 9.6 Hz),
3.54 (1H, dd, J ) 9.6, 10.1 Hz), 3.72 (3H, s), 3.74 (3H, s), 4.01
(1H, d, J ) 9.8 Hz), 4.34 (1H, dd, J ) 4.1, 10.1 Hz), 7.11-7.26
(5H, m); IR (film) 1737, 1676 cm-1; SIMS m/ z 477 (M+ + 1),
421, 245 (base). Anal. Calcd for C24H32N2O8: C, 60.49; H,
6.77; N, 5.88. Found: C, 60.20; H, 6.92; N, 5.73.
hexane); [R]25 -50.7 (c 1.00, MeOH); 1H NMR (CDCl3) δ 1.23
D
(3H, d, J ) 7.0 Hz), 1.44 (9H, s), 2.86 (3H, s), 3.23 (1H, dd, J
) 4.0, 9.6 Hz), 3.54 (1H, dd, J ) 9.6, 10.3 Hz), 4.01 (1H, d, J
) 11.1 Hz), 4.49-4.67 (2H, m), 4.99, 5.13 (2H, ABq, J ) 12.3
Hz), 5.12, 5.19 (2H, ABq, J ) 12.2 Hz), 7.19-7.35 (10H, m);
IR (KBr) 1742, 1679 cm-1; SIMS m/ z 539 (M+ + 1), 483, 235,
145, 91 (base). Anal. Calcd for C29H34N2O8: C, 64.67; H, 6.36;
N, 5.20. Found: C, 64.52; H, 6.37; N, 5.23.
ter t-Bu tyl (4S)-3-[(2R)-2-ben zyl-3,3-bis(m eth oxyca r bo-
n yl)p r op ion yl]-1-m eth yl-2-oxoim id a zolid in e-4-ca r boxy-
la te [(S,R)-8i]: colorless oil; [R]25 -15.9 (c 0.54, MeOH); 1H
D
NMR (CDCl3) δ 1.46 (9H, s), 2.84-2.96 (1H, m), 2.93 (3H, s),
3.25-3.36 (2H, m), 3.29 (3H, s), 3.67 (3H, s), 3.68-3.81 (2H,
m), 4.69 (1H, dd, J ) 4.1, 10.3 Hz), 4.91-5.02 (1H, m), 7.13-
ter t-Bu tyl (4S)-3-[(2S)-3,3-bis((ben zyloxy)ca r bon yl)-2-
m et h ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r -
boxyla te [(S,S)-8e]: colorless oil; [R]25D -37.7 (c 1.02, MeOH);
1H NMR (CDCl3) δ 1.19 (3H, d, J ) 7.0 Hz), 1.45 (9H, s), 2.89
(3H, s), 3.29 (1H, dd, J ) 4.4, 9.6 Hz), 3.66 (1H, dd, J ) 9.6,
10.0 Hz), 3.98 (1H, d, J ) 10.4 Hz), 4.49-4.67 (2H, m), 5.04-
7.42 (5H, m); IR (film) 1738, 1680 cm-1; SIMS m/ z 463 (M+
1), 407, 171 (base), 99. Anal. Calcd for C23H30N2O8: C, 59.73;
H, 6.54; N, 6.06. Found: C, 59.57; H, 6.44; N, 6.25.
+
ter t-Bu tyl (4S)-3-[(2S)-2-ben zyl-3,3-bis(m eth oxyca r bo-
n yl)p r op ion yl]-1-m eth yl-2-oxoim id a zolid in e-4-ca r boxy-
la te [(S,S)-8i]: colorless needles, mp 110-111 °C (Et2O/
hexane); [R]24D -104.3 (c 0.52, MeOH); 1H NMR (CDCl3) δ 1.45
(9H, s), 2.76 (3H, s), 2.83-3.04 (2H, m), 3.13 (1H, dd, J ) 3.7,
9.5 Hz), 3.28 (1H, dd, J ) 9.5, 9.8 Hz), 3.64 (3H, s), 3.70 (3H,
s), 3.92 (1H, d, J ) 9.2 Hz), 4.27 (1H, dd, J ) 3.7, 9.8 Hz),
5.01-5.13 (1H, m), 7.16-7.26 (5H, m); IR (KBr) 1735, 1682,
1668 cm-1; SIMS m/ z 463 (M+ + 1), 407, 203 (base), 171.
5.19 (4H, m), 7.15-7.35 (10H, m); IR (film) 1738, 1678 cm-1
;
SIMS m/ z 539 (M+ + 1), 483, 235, 145, 91 (base). Anal. Calcd
for C29H34N2O8: C, 64.67; H, 6.36; N, 5.20. Found: C, 64.37;
H, 6.41; N, 5.22.
ter t-Bu tyl (4S)-3-[(2R)-3,3-bis(m eth oxyca r bon yl)-2-eth -
ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r b oxy-
la te [(S,R)-8f]: colorless needles, mp 115-116 °C (Et2O/
hexane); [R]25 -43.7 (c 1.02, MeOH); 1H NMR (CDCl3) δ 0.97
D
(3H, t, J ) 7.5 Hz), 1.47 (9H, s), 1.57-1.98 (2H, m), 2.89 (3H,
s), 3.28 (1H, dd, J ) 4.7, 9.5 Hz), 3.64-3.76 (1H, m), 3.67 (3H,
s), 3.75 (3H, s), 3.98 (1H, d, J ) 11.1 Hz), 4.62-4.73 (2H, m);
IR (KBr) 1737, 1680 cm-1; SIMS m/ z 401 (M+ + 1), 345, 201,
173, 141 (base), 99. Anal. Calcd for C18H28N2O8: C, 53.99;
H, 7.05; N, 7.00. Found: C, 53.72; H, 6.91; N, 6.90.
ter t-Bu tyl (4S)-3-[(2R)-3,3-bis((ben zyloxy)ca r bon yl)-2-
eth ylp r op ion yl]-1-m eth yl-2-oxoim id a zolid in e-4-ca r boxy-
la te [(S,R)-8j]: colorless needles, mp 106-107 °C (Et2O/
hexane); [R]23 -53.1 (c 0.54, MeOH); 1H NMR (CDCl3) δ 0.93
D
(3H, t, J ) 7.5 Hz), 1.45 (9H, s), 1.54-2.05 (2H, m), 2.85 (3H,
s), 3.21 (1H, dd, J ) 4.6, 9.5 Hz), 3.52 (1H, dd, J ) 9.5, 10.4
Hz), 4.07 (1H, d, J ) 11.0 Hz), 4.49 (1H, dd, J ) 4.6, 10.4 Hz),
4.66-4.77 (1H, m), 4.96-5.21 (4H, m), 7.14-7.32 (10H, m);
ter t-Bu tyl (4S)-3-[(2S)-3,3-bis(m eth oxyca r bon yl)-2-eth -
ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r b oxy-
1
la te [(S,S)-8f]: colorless oil; [R]25 -69.1 (c 1.02, MeOH); H
D
IR (KBr) 1751, 1732, 1726, 1676 cm-1; SIMS m/ z 553 (M+
1), 497, 235, 91 (base). Anal. Calcd for C30H36N2O8: C, 65.20;
H, 6.57; N, 5.07. Found: C, 64.98; H, 6.64; N, 4.95.
+
NMR (CDCl3) δ 0.86 (3H, t, J ) 7.5 Hz), 1.47 (9H, s), 1.53-
1.92 (2H, m), 2.91 (3H, s), 3.28 (1H, dd, J ) 4.1, 9.6 Hz), 3.61-
3.70 (1H, m), 3.71 (3H, s), 3.74 (3H, s), 3.96 (1H, d, J ) 10.4
Hz), 4.54 (1H, dd, J ) 4.1, 10.2 Hz), 4.62-4.74 (1H, m); IR
(film) 1737, 1676 cm-1; SIMS m/ z 401 (M+ + 1), 345, 201
(base), 173, 141, 99. Anal. Calcd for C18H28N2O8: C, 53.99;
H, 7.05; N, 7.00. Found: C, 53.71; H, 7.14; N, 6.73.
ter t-Bu tyl (4S)-3-[(2S)-3,3-bis((ben zyloxy)ca r bon yl)-2-
eth ylp r op ion yl]-1-m eth yl-2-oxoim id a zolid in e-4-ca r boxy-
1
la te [(S,S)-8j]: colorless oil; [R]25 -44.8 (c 0.50, MeOH); H
D
NMR (CDCl3) δ 0.83 (3H, t, J ) 7.5 Hz), 1.44 (9H, s), 1.53-
1.83 (2H, m), 2.89 (3H, s), 3.28 (1H, dd, J ) 4.3, 9.6 Hz), 3.65
(1H, dd, J ) 9.6, 10.1 Hz), 4.06 (1H, d, J ) 10.4 Hz), 4.53 (1H,
dd, J ) 4.2, 10.1 Hz), 4.66-4.79 (1H, m), 5.04-5.13 (4H, m),
7.26-7.28 (10H, m); IR (film) 1737, 1674 cm-1; SIMS m/ z 553
(M+ + 1), 497, 235, 91 (base). Anal. Calcd for C30H36N2O8:
C, 65.20; H, 6.57; N, 5.07. Found: C, 64.90; H, 6.71; N, 5.13.
ter t-Bu t yl (4S)-3-[(2R)-3,3-b is(m et h oxyca r b on yl)-2-
isob u t ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r -
boxyla te [(S,R)-8g]: colorless prisms, mp 120-121 °C (Et2O/
hexane); [R]23D -67.8 (c 0.99, MeOH); 1H NMR (CDCl3) δ 0.89-
0.97 (6H, m), 1.14-1.40 (1H, m), 1.46 (9H, s), 1.60-1.77 (2H,
m), 2.90 (3H, s), 3.28 (1H, dd, J ) 5.1, 9.5 Hz), 3.64-3.73 (1H,
m), 3.67 (3H, s), 3.75 (3H, s), 3.81 (1H, d, J ) 9.8 Hz), 4.65
(1H, dd, J ) 5.1, 10.4 Hz), 4.78-4.89 (1H, m); IR (KBr) 1746,
1727, 1673 cm-1; SIMS m/ z 429 (M+ + 1), 373, 229, 169, 99
(base). Anal. Calcd for C20H32N2O8: C, 56.06; H, 7.53; N, 6.54.
Found: C, 56.21; H, 7.44; N, 6.45.
ter t-Bu tyl (4S)-3-[(2R)-3,3-bis((ben zyloxy)ca r bon yl)-2-
isob u t ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r -
boxyla te [(S,R)-8k ]: colorless oil; [R]23D -47.9 (c 0.65, MeOH);
1H NMR (CDCl3) δ 0.82-0.87 (6H, m), 1.25-1.44 (1H, m), 1.44
(9H, s), 1.58-1.76 (2H, m), 2.84 (3H, s), 3.18 (1H, dd, J ) 5.1,
9.5 Hz), 3.44 (1H, dd, J ) 9.5, 10.4 Hz), 3.89 (1H, d, J ) 9.6
Hz), 4.45 (1H, dd, J ) 5.1, 10.4 Hz), 4.79-4.91 (1H, m), 4.99-
ter t-Bu tyl (4S)-3-[(2S)-3,3-bis(m eth oxycar bon yl)-2-isobu -
t ylp r op ion yl]-1-m et h yl-2-oxoim id a zolid in e-4-ca r b oxy-
la te [(S,S)-8g]: colorless oil; [R]25 -73.2 (c 0.52, MeOH); 1H
5.21 (4H, m), 7.21-7.33 (10H, m); IR (film) 1737, 1680 cm-1
SIMS m/ z 581 (M+ + 1), 525, 235, 91 (base).
;
D
NMR (CDCl3) δ 0.86-0.92 (6H, m), 1.15-1.45 (1H, m), 1.47