A. Kaiser, M. Balbi / Tetrahedron: Asymmetry 10 (1999) 1001–1014
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mixture was shaken with saturated NaHCO3 solution (25 ml), the layers were separated, and the aqueous
layer was extracted with EtOAc (2×100 ml). The combined organic layers were washed with brine (2×15
ml), dried and evaporated.
4.4.1. (1S,3S)- and (1R,3S)-N-[3-Diphenylphosphinamido-1-(4-methoxyphenyl)-4-phenyl-1-butyl]-
formamide (syn-6a; anti-6a)
Pale yellow oil (diastereomeric mixture syn:anti, 60:40). The diastereomers were separated by column
chromatography (CH2Cl2:MeOH, 95:5). syn-6a was recrystallized from toluene.
syn-6a (1S,3S): Pale yellow crystals (1.06 g, 42%); m.p. 95°C; IR (KBr): 3211 (NH), 1665 (C_O),
1
1179 cm−1 (P_O). H NMR (CDCl3): δ (ppm)=1.93 (ddd, J=14.2, 8.2, 4.1 Hz, 1H, HCH), 2.39 (ddd,
J=14.2, 11.1, 3.7 Hz, 1H, HCH), 2.61 (s, 1H, NH, exchangeable), 2.62–2.80 [m, 1H, HCHPh, after H/D-
exchange: 2.66 (dd, J=13.5, 8.2 Hz)], 2.93–3.06 (m, 1H, HCHPh), 3.19–3.34 (m, 1H, CHNHPO), 3.75
(s, 3H, OCH3), 4.96–5.05 [m, 1H, CHNHCHO, after H/D-exchange: 5.09 (dd, J=11.1, 3.7 Hz)], 6.78,
7.16 (AA0BB0, J=8.7 Hz, 4H, ArH), 7.12–7.21 (m, 1H, ArH), 7.23–7.51 (m, 12H, ArH), 7.67–7.80 (m,
3H, NHCHO, exchangeable and 2H, ArH), 8.07 (s, 1H, NCHO). Anal. calcd for C30H31N2O3P (503.5):
20
D
C, 72.27; H, 6.27; N, 5.62. Found: C, 72.02; H, 6.47; N, 5.42. [α] =−77.15 (c=0.15, CHCl3).
anti-6a (1R,3S): Colorless crystals (0.88 g, 35%); m.p. 75°C; IR (KBr): 3210 (NH), 1665 (C_O),
1
1179 cm−1 (P_O). H NMR (CDCl3): δ (ppm)=1.91–2.07 (m, 1H, HCH), 2.25–2.49 (m, 1H, HCH),
2.78 (d, J=6.6 Hz, 2H, PhCH2), 2.96–3.07 (m, 1H, NH, exchangeable), 3.14–3.31 (m, 1H, CHNHPO),
3.77 (s, 3H, OCH3), 5.20–5.28 [m, 1H, CHNHCHO, after H/D-exchange: 5.23 (dd, J=7.0, 5.2 Hz)],
6.76, 7.16 (AA0BB0, J=8.7 Hz, 4H, ArH), 6.94–7.03 (m, 2H, ArH), 7.21–7.57 (m, 11H, ArH), 7.72–7.85
(m, 2H, ArH), 8.10 (d, J=7.7 Hz, 1H, NHCHO, exchangeable), 8.14 (s, 1H, NCHO). Anal. calcd for
20
D
C30H31N2O3P (503.5): C, 72.27; H, 6.27; N, 5.62. Found: C, 72.12; H, 6.49; N, 5.43. [α] =−11.8
(c=0.45, CHCl3).
4.4.2. (1S,3S)- and (1R,3S)-N-[3-Diphenylphosphinamido-1-(4-methoxyphenyl)-5-methyl-1-hexyl]-
formamide (syn-6b; anti-6b)
Pale yellow oil (diastereomeric mixture; syn:anti, 50:50). The diastereomers were separated by column
chromatography (CH2Cl2:MeOH, 95:5). In addition to 0.13 g (9%) of a colorless oil (diastereomeric
mixture; syn:anti, 50:50), the following were obtained.
syn-6b (1S,3S): Colorless foam (0.48 g, 34%); IR (KBr): 3433 (NH), 1665 (C_O), 1181 cm−1 (P_O).
1H NMR (CDCl3): δ (ppm)=0.69 (d, J=6.6 Hz, 3H, CH3), 0.81 (d, J=6.6 Hz, 3H, CH3), 1.41 (dd, J=7.0
Hz, 2H, CH2CH(CH3)2), 1.67–1.97 (m, 2H, CH(CH3)2 and HCH), 2.40 (ddd, J=14.2, 10.8, 3.8 Hz, 1H,
HCH), 2.78–2.89 (m, 1H, NH, exchangeable), 3.05–3.21 (m, 1H, CHNH), 3.76 (s, 3H, OCH3), 4.90–5.01
[m, 1H, CHNHCHO, after H/D-exchange: 4.98 (dd, J=10.8, 4.0 Hz)], 6.80, 7.22 (AA0BB0, J=8.7 Hz, 4H,
ArH), 7.40–7.58 (m, 6H, ArH), 7.70 (d, J=7.6 Hz, NH, exchangeable), 7.77–7.99 (m, 4H, ArH), 8.14 (s,
1H, NCHO). Anal. calcd for C27H33N2O3P (464.5): C, 69.81; H, 7.16; N, 6.03. Found: C, 69.76; H, 7.21;
20
D
N, 5.99. [α] =−98.0 (c=1.34, CHCl3).
anti-6b (1R,3S): Colorless foam (0.48 g, 34%); IR (KBr): 3205 (NH), 1669 (C_O), 1181 cm−1
1
(P_O). H NMR (CDCl3): δ (ppm)=0.60–0.69 (m, 6H, 2CH3), 1.23–1.70 (m, 3H, CH2CH(CH3)2 and
CH(CH3)2), 1.88 (ddd, J=14.6, 5.0, 4.9 Hz, 1H, HCH), 2.32 (ddd, J=14.6, 8.4, 4.7 Hz, 1H, HCH),
2.90–3.08 (m, 2H, CHNH and NH, exchangeable), 3.77 (s, 3H, OCH3), 5.13–5.21 [m, 1H, CHNHCHO,
after H/D-exchange: 5.16 (dd, J=8.4, 4.7 Hz)], 6.80, 7.25 (AA0BB0, JAB=8.7 Hz, 4H, ArH), 7.38–7.60
(m, 6H, ArH), 7.79–7.99 (m, 4H, ArH), 8.14 (s, 1H, NCHO), 8.35 (d, J=7.9 Hz, 1H, NH, exchangeable).
Anal. calcd for C27H33N2O3P (464.5): C, 69.81; H, 7.16; N, 6.03. Found: C, 69.80; H, 7.33; N, 5.97.
20
D
[α] =−30.3 (c=1.14, CHCl3).