2040
Z.-H. XIAO ET AL.
J ¼ 6.4, 6.0, 4.5 Hz, 1H, H-4), 4.02 (d, J ¼ 11.7 Hz, 1H, OCH2), 4.57 (d, J ¼ 11.7 Hz,
OCH2), 5.02 (d, J ¼ 15.1 Hz, 1H, NCH2), 7.20–7.40 (m, 10H, Ph-H). 13C NMR
(100 MHz, CDCl3): d 9.65, 19.92, 37.08, 43.96 (NCH2), 61.62 (OCH2), 71.31,
72.79, 127.41 (2C), 127.52 (2C), 127.79 (2C), 128.41 (2C), 128.61 (2C), 136.59,
þ
=
137.62, 172.84 (C O). MS (ESI): 310 (M þ H , 100). Anal. calcd. for C20H23NO2:
C, 77.67; H, 7.44; N, 4.53. Found: C, 77.37; H, 7.64; N, 4.62.
(4S,5S)-1-Benzyl-4-benzyloxy-5-(n-propyl)-2-pyrrolidinone (7c)
Yield: 75%, cis=trans ¼ 81:19, inseparable by column chromatography. IR
1
(film) nmax: 2968, 2932, 1693, 1454, 1421, 1068 cmꢀ1. H NMR (400 MHz, CDCl3):
d 0.88 (t, J ¼ 7.2 Hz, 3H, CH3), 1.15–1.38 (m, 2H), 1.53–1.63 (m, 1H), 1.67–1.80 (m,
1H), 2.55 (dd, J ¼ 16.8, 6.2 Hz, 1H, H-3), 2.62 (dd, J ¼ 16.8, 4.4 Hz, 1H, H-3), 3.51
(ddd, J ¼ 5.9, 4.0, 2.0 Hz, 1H, H-5), 3.97 (d, J ¼ 15.1 Hz, NCH2), 4.10 (ddd,
J ¼ 6.2, 5.9, 4.4 Hz, 1H, H-4), 4.41 (d, J ¼ 11.7 Hz, 1H, OCH2), 4.57 (d, J ¼ 11.7 Hz,
OCH2), 5.03 (d, J ¼ 15.1 Hz, 1H, NCH2), 7.20–7.40 (m, 10H, Ph-H). 13C NMR
(100 MHz, CDCl3): d14.31, 18.64, 29.10, 37.04, 44.04 (NCH2), 60.45 (OCH2),
71.32, 73.03, 127.40 (2C), 127.54 (2C), 127.82 (2Cþ), 128.44 (2C), 128.61 (2C),
=
136.66, 137.68, 172.80 (C O). MS (ESI): 324 (M þ H , 100). HRESIMS calcd. for
[C21H25NO2þH]þ: 324.1964; found: 324.1966.
(4S,5S)-1-Benzyl-4-benzyloxy-5-(n-butyl)-2-pyrrolidinone (7d)
25
Yield: 58%, cis=trans ¼ 71:29. Wax solid. ½aꢃD þ 13:1 (c 1.2, CHCl3). IR (film)
1
n
max: 2955, 2930, 1693, 1454, 1420, 1094 cmꢀ1. H NMR (400 MHz, CDCl3): d 0.85
(t, J ¼ 6.7 Hz, 3H, CH3), 1.12–1.30 (m, 4H), 1.62 (m, 1H), 1.75 (m, 1H), 2.55 (dd,
J ¼ 16.8, 6.4 Hz, 1H, H-3), 2.63 (dd, J ¼ 16.8, 4.5 Hz, 1H, H-3), 3.50 (ddd, J ¼ 5.8,
3.9, 1.9 Hz, 1H, H-5), 3.97 (d, J ¼ 15.2 Hz, 1H, NCH2), 4.11 (ddd, J ¼ 6.4, 5.8,
4.5 Hz, 1H, H-4), 4.39 (d, J ¼ 11.7 Hz, 1H, OCH2), 4.57 (d, J ¼ 11.7 Hz, OCH2),
5.04 (d, J ¼ 15.2 Hz, 1H, NCH2), 7.20–7.40 (m, 10H, Ph-H). 13C NMR (100 MHz,
CDCl3): d 13.95, 22.91, 26.59, 27.38, 37.08, 44.04 (NCH2), 60.62 (OCH2), 71.30,
72.95, 127.45 (2C), 127.62 (2C), 127.86 (2C), 128.44 (2C), 128.65 (2C), 136.66,
þ
=
137.66, 172.85 (C O). MS (ESI): 338 (M þ H , 100). Anal. calcd. for C22H27NO2:
C, 78.34; H, 8.01; N, 4.15. Found: C, 78.01; H, 8.23; N, 4.24.
(4S,5S)-1-Benzyl-4-benzyloxy-5-(i-butyl)-2-pyrrolidinone (7e)
Yield: 48%, cis=trans ¼ 58:42, inseparable by column chromatography. IR
1
(film) nmax: 2955, 2929, 1692, 1454, 1419, 1095 cmꢀ1. H NMR (400 MHz, CDCl3):
d0.80 (d, J ¼ 6.6 Hz, 3H, CH3), 0.90 (d, J ¼ 6.6 Hz, 3H, CH3), 1.30–1.44 (m, 1H),
1.52–1.66 (m, 1H), 1.75–1.85 (m, 1H), 2.54 (dd, J ¼ 16.6, 6.0 Hz, 1H, H-3), 2.64
(dd, J ¼ 16.6, 3.8 Hz, 1H, H-3), 3.54 (ddd, J ¼ 5.8, 4.4, 1.0 Hz, 1H, H-5), 3.93 (d,
J ¼ 15.2 Hz, 1H, NCH2), 4.08 (ddd, J ¼ 6.0, 5.8, 3.8 Hz, 1H, H-4), 4.38 (d,
J ¼ 11.7 Hz, 1H, OCH2), 4.56 (d, J ¼ 11.7 Hz, 1H, OCH2), 5.06 (d, J ¼ 15.1 Hz,
NCH2), 7.20–7.40 (m, 10H, Ph-H). 13C NMR (100 MHz, CDCl3): d21.80, 23.68,
24.68, 35.32, 36.96, 43.97 (NCH2), 61.42 (OCH2), 71.13, 73.06, 127.41 (2C),
=
127.53 (2C), 127.83 (2C), 128.38 (2C), 128.58 (2C), 136.57, 137.59, 172.86 (C O).