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Organic & Biomolecular Chemistry
cation by column chromatography on silica gel, using ethyl C(5)H2], 71.5 [CH, CH3SO2C(3)H], 165.7 (C, CO); IR (film) νmax
acetate–hexane (10 : 90–40 : 60 gradient) as eluent gave 3-[(2- (cm−1) 2967, 2934, 2876, 1694 (CvO), 1491, 1452, 1304 (SvO),
ethylphenyl)sulfony]-4-methyl-1-propylpyrrolidin-2-one
7b 1268, 1141 (SvO); HRMS-ESI (m/z): [M + H]+ calcd for
(62 mg, 69%) as a colourless oil. Due to the presence of C9H18NO3S, 220.0997; found: 220.1007; ESI m/z: [M + Na]+
1
additional peaks [δH 4.21–4.32 (m)] in the H NMR spectra of 242.3.
the purified product, a second purification was carried out
using column chromatography on silica gel, using ethyl din-2-one
trans 4-Methyl-3-[(3-phenylpropyl]sulfonyl)-1-propylpyrroli-
7d. N,N-Dipropyl-2-[(3-phenylpropyl)sulfonyl]-2-
acetate–hexane (5 : 95–40 : 60 gradient) as eluent, 3-[(2-ethyl- diazoacetamide 6d (200 mg, 0.57 mmol), copper(II) chloride
phenyl)sulfony]-4-methyl-1-propylpyrrolidin-2-one 7b [53 mg, (3.8 mg, 28.4 μmol), (+)-2,2′-isopropylidenebis[(4R)-4-phenyl-2-
59% (100% trans γ-lactam 7b)] was isolated as a colourless oil.
oxazoline] 1 (11.4 mg, 34.1 μmol), sodium tetrakis[3,5-bis(tri-
Characterisation data for trans-3-[(2-ethylphenyl)sulfony]-4- fluoromethyl)phenyl]borate (NaBARF) (30.3 mg, 34.1 μmol)
methyl-1-propylpyrrolidin-2-one 7b; 1H NMR (600 MHz, δ) 0.89 and dichloromethane (60 mL) were used following the pro-
(t, J = 7.4 Hz, CH3CH2CH2N, 3H), 1.29 [d, J = 7.1, CH3C(4)H, cedure described for method A, with a reaction time of
1
3H], 1.33 (t, J = 7.5 Hz, ArCH2CH3, 3H), 1.47–1.60 (m, 18 hours, to give the crude product 7d. H NMR spectroscopy
CH3CH2CH2N, 2H,), 2.91 [dd, J = 9.6, 3.2 Hz, 1H of C(5)H2, of the crude product showed that the reaction was approxi-
1H], 2.94–3.31 (m, ArCH2CH3, 2H), 3.14–3.23 [m, C(4)H and mately 80–90% efficient (95% trans γ-lactam 7d: 5% cis
1H of CH3CH2CH2N, 2H,], 3.24–3.33 (m, 1H of CH3CH2CH2N, γ-lactam 8d). Purification by column chromatography on silica
1H,), 3.63 [d, J = 3.9 Hz, C(3)H, 1H,], 3.79 [dd, J = 9.4, 7.8 Hz, gel, using ethyl acetate–hexane (10 : 90) as eluent gave a
1H of C(5)H2, 1H,], 7.37 [dd appears as t, J = 7.7 Hz, C(4′)H, mixture of products [139 mg, 76% (95% trans γ-lactam 7d: 5%
1H], 7.41 [d, J = 7.7 Hz, C(3′)H, 1H], 7.58 [dd appears as t, J = cis γ-lactam 8d)] as a colourless oil.
7.5 Hz, C(5′)H, 1H], 7.96 [d, J = 8.0 Hz, C(6′)H, 1H]; 13C NMR
Characterisation data for trans 4-methyl-3-[(3-phenylpropyl]-
(150 MHz, δ) 11.1 (CH3, CH3CH2CH2N), 16.1 (CH3, ArCH2CH3), sulfonyl)-1-propylpyrrolidin-2-one 7d; IR (film) νmax (cm−1
)
20.3 (CH2, CH3CH2CH2N), 20.9 [CH3, CH3C(4)H], 26.4 (CH2, 2965, 2934, 2876, 1693 (CvO), 1454, 1308, 1139, 1125 (SvO),
ArCH2CH3), 27.5 [CH, C(4)H], 44.7 (CH2, CH3CH2CH2N), 53.0 701 (CS); 1H NMR (600 MHz, δ) 0.92 (t, J = 7.4 Hz,
[CH2, C(5)H2], 73.1 [CH, C(3)H], 126.2 (CH, aromatic, CH), CH3CH2CH2N, 3H), 1.29 [d, J = 7.0 Hz, CH3C(4)H, 3H],
130.9 (CH, aromatic, CH), 131.5 (CH, aromatic, CH), 134.2 1.50–1.62 (m, CH3CH2CH2N, 2H), 2.16–2.27 [m, C(2′)H2, 2H],
(CH, aromatic, CH), 135.7 (C, aromatic, C), 144.8 (C, aromatic, 2.74–2.84 [m, C(3′)H2, 2H], 2.94 [dd, J = 9.7, 3.9 Hz, 1H of C(5)-
C), 164.8 (C, CO); IR (film) νmax (cm−1) 2967, 2935, 2876, 1699 H2, 1H], 3.05–3.14 [m, CH3C(4)H, 1H], 3.19–3.28 (m,
(CvO), 1439, 1308, 1151, 1133 (SvO); HRMS-ESI (m/z): [M + CH3CH2CH2N, 1H), 3.29–3.36 (m, CH3CH2CH2N, 1H),
H]+ calcd for C16H24NO3S, 310.1477; found 310.1466; ESI m/z: 3.37–3.43 [m, C(1′)H2, 2H], 3.45 [d, J = 4.7 Hz, C(3)H, 1H],
[M + H]+ 310.3.
3.67–3.77 [m, 1H of C(5)H2, 1H], 7.16–7.24 (m, ArH, 3H),
Spectral data for cis-4-methyl-3-[(2-ethylphenyl)sulfonyl]-1- 7.25–7.33 (m, ArH, 3H,); 13C NMR (150 MHz, δ) 11.1 (CH3,
propylpyrrolidin-2-one 8b (tentative assignment); 1H NMR CH3CH2CH2N), 20.3 (CH2, CH3CH2CH2N), 20.9 [CH3, CH3C(4)-
(400 MHz, δ) 1.65 [d, J = 7.2 Hz, CH3C(4)H, 3H], 3.90 [d, J = 8.3 H], 23.4 [CH2, C(2′)H2], 25.8 [CH, CH3C(4)H], 34.4 [CH2, C(3′)-
Hz, C(3)H, 1H], 7.89 (dd, J = 8.0, 1.4 Hz, C(6′)H, 1H).
H2], 44.8 (CH2, CH3CH2CH2N), 51.8 [CH2, C(1′)H2], 53.3 [CH2,
trans-4-Methyl-3-(methylsulfonyl)-1-propylpyrrolidin-2-one 7c. C(5)H2], 69.8 [CH, C(3)H], 126.3 (CH, aromatic CH), 128.4 (CH,
N,N-Dipropyl-2-methylsulfonyl-2-diazoacetamide, 6c (100 mg, 2 × aromatic CH), 128.7 (CH, 2 × aromatic CH), 140.2 (C, aro-
0.40 mmol), rhodium(II) acetate (1.9 mg, 1 mol%) and matic C), 165.7 (C, CO); HRMS-ESI (m/z): [M + H]+ calcd for
dichloromethane (40 mL) were used following the procedure C17H26NO3S, 324.1633; found: 324.1629; ESI m/z: [2M + H]+
1
described for method B, with a reaction time of 18 hours. H 647.3.
NMR spectroscopy of the crude product showed that the reac-
Spectral data for cis-4-methyl-3-[(4-phenylpropyl)sulfonyl]-1-
tion was approximately 90% efficient (100% trans γ-lactam 7c). propylpyrrolidin-2-one 8d (tentative assignment); 1H NMR
Purification by column chromatography on silica gel, using (400 MHz, δ) 0.95 (t, J = 7.4 Hz, CH3CH2CH2N, 3H), 3.73 [d, J =
ethyl acetate in hexane (0–100–100–0 gradient) as eluent, gave 8.6 Hz, C(3)H, 1H]; 13C NMR (150 MHz, δ) 13.8 (CH3), 20.5
trans-4-methyl-3-(methylsulfonyl)-1-propylpyrrolidin-2-one 7c (CH2), 23.4 (CH2), 31.9 (CH), 44.8 (CH2), 53.3 (CH2), 53.5
(48 mg, 54%) as a colourless oil.
(CH2), 65.7 (CH), 126.3 (CH, aromatic CH), 128.5 (CH, aromatic
Characterisation data for trans-4-methyl-3-(methylsulfonyl)- CH), 140.2 (C, aromatic C), 166.7 (C, CO).
1
1-propylpyrrolidin-2-one 7c; H NMR (300 MHz, δ) 0.92 (t, J =
trans
4-Methyl-3-[(4-phenylbutyl)sulfonyl]-1-propylpyrroli-
7.4 Hz, CH3CH2CH2N, 3H), 1.32 [d, J = 7.0 Hz, CH3C(4)H, 3H], din-2-one
7e. N,N-Dipropyl-2-[(4-phenylbutyl)sulfonyl]-2-di-
1.51–1.64 (m, CH3CH2CH2N, 2H), 2.96 [dd, J = 9.7, 4.0 Hz, 1H azoacetamide 6e (100 mg, 0.27 mmol), rhodium(II) acetate
of C(5)H2, 1H], 3.03–3.17 [m CH3C(4)H, 1H], 3.22 [s, (∼1 mg) and dichloromethane (40 mL) were used following the
CH3SO2C(3)H, 3H], 3.23–3.40 (m, CH3CH2CH2N, 2H), 3.47 [d, procedure described for method B, with a reaction time of
J = 4.8 Hz, CH3SO2C(3)H, 1H], 3.69–3.76 [m, 1H of C(5)H2, 1H]; 6 hours, to give the crude product 7e. 1H NMR spectroscopy of
13C NMR (75 MHz, δ) 11.1 (CH3, CH3CH2CH2N), 20.3 (CH2, the crude product showed that the reaction was approximately
CH3CH2CH2N) 20.7 [CH3, CH3C(4)H], 26.0 [CH, CH3C(4)H], 90% efficient (95% trans γ-lactam 7e: 5% cis γ-lactam 8e). Puri-
40.5 (CH3, CH3SO2), 44.8 (CH2, CH3CH2CH2N), 53.0 [CH2, fication by column chromatography on silica gel, using ethyl
7626 | Org. Biomol. Chem., 2014, 12, 7612–7628
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