A New Synthesis of Polyfunctionalized 2-Alkyl-1,4-diketones

Abstract

The reactivity of silyl enol ethers with β-nitroenones was successfully exploited for synthesizing functionalized polycarbonyl frameworks, in very short reaction times and in good yields.

Key words

Michael addition - enones - nitro compounds - silyl enol ethers - 1,4-dicarbonyl derivatives

• References and Notes

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• 4a Ballini R, Rinaldi A. Tetrahedron Lett. 1994; 35: 9247
• 4b Ballini R, Bosica G. Tetrahedron 1995; 51: 4213
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• 4d Ballini R, Fiorini D, Gil MV, Palmieri A, Román E, Serrano JA. Tetrahedron Lett. 2003; 44: 2795
• 4e Ballini R, Bosica G, Palmieri A, Petrini M, Pierantozzi C. Tetrahedron 2003; 59: 7283
• 5a Ballini R, Bosica G, Damiani M, Righi P. Tetrahedron 1999; 55: 13451
• 5b Ballini R, Bosica G, Fiorini D, Gil MV, Palmieri A. Synthesis 2004; 605
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• 5e Ballini R, Bosica G. Synlett 1996; 1115
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• 7 Ballini R, Bosica G, Gabrielli S, Palmieri A. Tetrahedron 2009; 65: 2916

β-Nitroenones were synthesized according to:
• 8a Ballini R, Fiorini D, Palmieri A. Tetrahedron Lett. 2004; 45: 7027
• 8b Palmieri A, Gabrielli S, Ballini R. Green Chem. 2013; 15: 2344
• 9 General Procedureβ-Nitroenone 5 (1.0 mmol) was dissolved in anhyd CH₂Cl₂ (10 mL) and the solution was cooled, under nitrogen atmosphere, to –45 °C. Then, 6 (1.3 mmol) was added to the reaction mixture, followed by a solution of 1 M Bu₄NF (1.5 mL in THF, 1.5 mmol) that was slowly dropped (over 15 min). The reaction was stirred for 1 h, and then treated with distillated H₂O (50 mL). The aqueous layer was extracted with CH₂Cl₂ (3 × 30 mL) and the collected organic layers were dried over anhyd Na₂SO₄. The solution was filtered and concentrated until the volume was reduced to 4 mL (WARNING: the complete evaporation of the solvent leads to nitrous acid elimination) and then passed through a short pad of silica gel (3 g) washing with fresh EtOAc (20 mL). Finally, the solvent was evaporated under reduced pressure, and the crude product 3 was purified by flash column chromatography (hexane–EtOAc, 90:10).5,5-Dimethyl-2-(1-nitropropyl)-1-phenylhexane-1,4-dione (3aa)Obtained as a mixture of diastereomers (dr = 65:35).Major diastereomer; white solid; mp 75–77 °C. IR (Nujol): 1358, 1549, 1677, 1702 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.85 (t, J = 7.3 Hz, 3 H), 1.08 (s, 9 H), 1.47–1.64 (m, 1 H), 1.81–1.98 (m, 1 H), 2.70 (dd, J = 18.4, 3.4 Hz, 1 H), 3.38 (dd, J = 18.4, 9.8 Hz, 1 H), 4.46 (td, J = 9.8, 3.4 Hz, 1 H), 4.52–4.59 (m, 1 H), 7.52 (t, J = 7.7 Hz, 2 H), 7.58–7.68 (m, 1 H), 8.06 (d, J = 7.7 Hz, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 10.6, 26.0, 26.6, 38.4, 44.0, 44.2, 91.7, 129.0, 129.2, 134.0, 137.2, 199.7, 213.3. MS (EI, 70 eV): m/z = 248, 201, 105 (100), 77, 57, 41. Anal. Calcd for C₁₇H₂₃NO₄ (305.37): C, 66.86; H, 7.59; N, 4.59. Found: C, 66.92; H, 7.62; N, 4.56.Minor diastereomer: white solid; mp 79–90 °C. IR (Nujol): 1353, 1551, 1672, 1695 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.91 (t, J = 7.3 Hz, 3 H), 1.13 (s, 9 H), 1.64–1.76 (m, 1 H), 1.94–2.07 (m, 1 H), 2.78 (dd, J = 18.4, 3.8 Hz, 1 H), 3.29 (dd, J = 18.4, 9.4 Hz, 1 H), 4.62–4.75 (m, 2 H), 7.47–7.66 (m, 3 H), 8.01–8.05 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 10.7, 23.0, 26.7, 35.1, 44.2, 44.3, 89.4, 128.8, 129.1, 134.1, 135.6, 198.5, 213.0. MS (EI, 70 eV): m/z = 248, 201, 105, 77, 57, 41. Anal. Calcd for C₁₇H₂₃NO₄ (305.37): C, 66.86; H, 7.59; N, 4.59. Found: C, 66.90; H, 7.62; N, 4.612-(1-Nitropropyl)-1-phenylpentane-1,4-dione (3ab)Obtained as a mixture of diastereomers (dr = 70:30).Major diastereomer: yellow oil. IR (neat): 1363, 1551, 1678, 1716 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.87 (t, J = 7.3 Hz, 3 H), 1.50–1.62 (m, 1 H), 1.84–1.98 (m, 1 H), 2.11 (s, 3 H), 2.69 (dd, J = 18.4, 3.0 Hz, 1 H), 3.26 (dd, J = 18.4, 9.4 Hz, 1 H), 4.45 (td, J = 12.4, 9.4, 3.0 Hz, 1 H), 4.52–4.60 (m, 1 H), 7.52 (t, J = 7.7 Hz, 2 H), 7.62 (t, J = 7.7 Hz, 1 H), 8.05 (d, J = 7.7 Hz, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 10.7, 25.9, 29.8, 44.1, 44.2, 91.5, 129.0, 129.2, 134.1, 136.9, 199.4, 205.3. MS (EI, 70 eV): m/z = 217, 105 (100), 77, 43. Anal. Calcd for C₁₄H₁₇NO₄ (263.29): C, 63.87; H, 6.51; N, 5.32. Found: C, 63.92; H, 6.54; N, 5.29.Minor diastereomer: yellow oil. IR (neat): 1362, 1548, 1676, 1702 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.91 (t, J = 7.3 Hz, 3 H), 1.63–1.74 (m, 1 H), 1.90–2.05 (m, 1 H), 2.18 (s, 3 H), 2.74 (dd, J = 18.4, 4.3 Hz, 1 H), 3.19 (dd, J = 18.4, 8.5 Hz, 1 H), 4.64–4.78 (m, 2 H), 7.49–7.54 (m, 2 H), 7.60–7.65 (m, 1 H), 8.01–8.04 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 10.7, 22.9, 30.1, 41.1, 44.2, 89.1, 128.9, 129.3, 134.2, 135.4, 198.2, 205.1. MS (EI, 70 eV): m/z = 217, 105 (100), 77, 43. Anal. Calcd for C₁₄H₁₇NO₄ (263.29): C, 63.87; H, 6.51; N, 5.32. Found: C, 63.91; H, 6.55; N, 5.30.2-(1-Nitropropyl)-1,4-diphenylbutane-1,4-dione (3ac)Obtained as a mixture of diastereomers (dr = 55:45).Major diastereomer: yellow oil. IR (neat): 1364, 1552, 1675, 1708 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.90 (t, J = 7.3 Hz, 3 H), 1.55–1.67 (m, 1 H), 1.91–2.04 (m, 1 H), 3.24 (dd, J = 18.0, 3.0 Hz, 1 H), 3.87 (dd, J = 18.0, 9.8 Hz, 1 H), 4.62–4.72 (m, 2 H), 7.40–7.47 (m, 2 H), 7.51–7.59 (m, 3 H), 7.61–7.67 (m, 1 H), 7.87–7.91 (m, 2 H), 8.10–8.15 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 10.7, 26.0, 40.0, 44.2, 91.8, 128.4, 128.9, 129.1, 129.2, 134.0, 134.1, 135.8, 137.2, 196.9, 199.4. MS (EI, 70 eV): m/z = 278, 173, 105 (100), 77, 51. Anal. Calcd for C₁₉H₁₉NO₄ (325.36): C, 70.14; H, 5.89; N, 4.31. Found: C, 70.19; H, 5.94; N, 4.28.Minor diastereomer: yellow oil. IR (neat): 1359, 1550, 1678, 1700 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.94 (t, J = 7.3 Hz, 3 H), 1.73–1.85 (m, 1 H), 2.00–2.13 (m, 1 H), 3.33 (dd, J = 18.0, 3.8 Hz, 1 H), 3.73 (dd, J = 18.0, 8.5 Hz, 1 H), 4.80–4.93 (m, 2 H), 7.42–7.65 (m, 6 H), 7.91–7.96 (m, 2 H), 8.07–8.12 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 10.7, 23.2, 36.9, 44.3, 89.4, 128.4, 128.9, 129.0, 129.3, 134.0, 134.2, 135.5, 136.1, 196.6, 198.3. MS (EI, 70 eV): m/z = 278, 173, 105 (100), 77, 51. Anal. Calcd for C₁₉H₁₉NO₄ (325.36): C, 70.14; H, 5.89; N, 4.31. Found: 70.18; H, 5.87; N, 4.34.1-(4-Methoxyphenyl)-2-(1-nitro-3-phenylpropyl)pentane-1,4-dione (3bb)Obtained as a mixture of diastereomers (dr = 75:25).Major diastereomer: yellow oil. IR (neat): 1364, 1556, 1594, 1668, 1709 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.78–1.90 (m, 1 H), 2.09 (s, 3 H), 2.19–2.32 (m, 1 H), 2.45–2.64 (m, 2 H), 2.66 (dd, J = 18.4, 3.4 Hz, 1 H), 3.18 (dd, J = 18.4, 9.4 Hz, 1 H), 3.87 (s, 3 H), 4.44 (td, J = 9.0, 3.4 Hz, 1 H), 4.65–4.72 (m, 1 H), 6.92–6.97 (m, 2 H), 7.03 (d, J = 7.7 Hz, 2 H), 7.14–7.33 (m, 3 H), 7.93–8.01 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 29.9, 32.2, 33.7, 43.8, 44.1, 55.8, 89.4, 114.4, 126.8, 128.6, 128.9, 129.6, 131.4, 139.3, 164.5, 197.3, 205.2. MS (EI, 70 eV): m/z = 322, 279, 189, 135 (100), 91, 77, 43. Anal. Calcd for C₂₁H₂₃NO₅ (369.42): C, 68.28; H, 6.28; N, 3.79. Found: 68.25; H, 6.25; N, 3.82.Minor diastereomer: white solid; mp 139–141 °C. IR (Nujol): 1357, 1558, 1596, 1672, 1721 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.82–1.93 (m, 1 H), 2.15 (s, 3 H), 2.25–2.37 (m, 1 H), 2.40–2.50 (m, 1 H), 2.60–2.72 (m, 2 H), 3.17 (dd, J = 18.4, 9.0 Hz, 1 H), 3.88 (s, 3 H), 4.60–4.66 (m, 1 H), 4.75–4.81 (m, 1 H), 6.95 (d, J = 9.0 Hz, 2 H), 7.03–7.07 (m, 2 H), 7.12–7.26 (m, 3 H) 7.97 (d, J = 9.0 Hz, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 30.2, 30.9, 32.2, 40.8, 44.2, 55.8, 86.8, 114.4, 126.7, 128.1, 128.5, 128.8, 131.3, 139.5, 164.4, 196.2, 205.2. MS (EI, 70 eV): m/z = 322, 279, 189, 135 (100), 91, 77, 43. Anal. Calcd for C₂₁H₂₃NO₅ (369.42): C, 68.28; H, 6.28; N, 3.79. Found: 68.31; H, 6.30; N, 3.83.1-(4-Methoxyphenyl)-2-(1-nitro-3-phenylpropyl)-4-phenylbutane-1,4-dione (3bc)Obtained as a mixture of diastereomers (dr = 65:35).Diastereomeric mixture: yellow oil. IR (neat): 1356, 1552, 1673, 1721, 1738 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.84–2.09 (m, 1 H), 2.26–2.79 (m, 3 H), 3.17–3.26 (m, 1 H), 3.73 (dd, J = 18.4, 8.5 Hz, 0.35 H), 3.81 (dd, J = 18.0, 9.4 Hz, 0.65 H), 3.38 (s, 3 H), 4.68 (dt, J = 9.0, 3.0 Hz, 0.65 H), 4.77–4.92 (m, 1.35 H), 6.94–7.01 (m, 2 H), 7.02–7.11 (m, 2 H), 7.14–7.30 (m, 3 H), 7.38–7.48 (m, 2 H), 7.50–7.60 (m, 1 H), 7.85–7.95 (m, 2 H), 8.02–8.12 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 31.2, 32.3, 33.8, 36.6, 39.9, 43.9, 44.3, 55.8, 87.1, 89.7, 114.5, 126.7, 126.8, 127.9, 128.4, 128.6, 128.9, 129.0, 129.2, 129.9, 131.4, 131.5, 133.9, 135.9, 136.2, 139.3, 139.6, 164.4, 196.4, 196.7, 196.8, 197.4. MS (EI, 70 eV): m/z = 384, 279, 135, 105 (100), 77. Anal. Calcd for C₂₆H₂₅NO₅ (431.49): C, 72.37; H, 5.84; N, 3.25. Found: C, 72.41; H, 5.87; N, 3.21.5,5-Dimethyl-2-(1-nitropentyl)-1-phenylhexane-1,4-dione (3ca)Obtained as a mixture of diastereomers (dr = 55:45).Major diastereomer: yellow oil. IR (neat): 1365, 1555, 1674, 1703 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.78 (t, J = 7.3 Hz, 3 H), 1.09 (s, 9 H), 1.11–1.28 (m, 4 H), 1.35–1.54 (m, 1 H), 1.82–1.98 (m, 1 H), 2.69 (dd, J = 18.0, 3.0 Hz, 1 H), 3.36 (dd, J = 18.0, 9.8 Hz, 1 H), 4.17–4.49 (m, 1 H), 4.60–4.69 (m, 1 H), 7.52 (t, J = 7.7 Hz, 2 H), 7.58–7.66 (m, 1 H), 8.05 (d, J = 7.7 Hz, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 13.8, 22.0, 26.6, 28.1, 32.1, 38.3, 44.1, 44.3, 90.1, 129.0, 129.2, 134.0, 137.2, 199.7, 213.3. MS (EI, 70 eV): m/z = 276, 229, 105 (100), 77, 57. Anal. Calcd for C₁₉H₂₇NO₄ (333.43): C, 68.44; H, 8.16; N, 4.20. Found: 68.49; H, 8.19; N, 4.18.Minor diastereomer: yellow oil. IR (neat): 1365, 1549, 1683, 1706 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.84 (t, J = 7.3 Hz, 3 H) 1.14 (s, 9 H), 1.01–1.34 (m, 4 H), 1.69–1.51 (m, 1 H), 1.92–2.06 (m, 1 H), 2.78 (dd, J = 18.0, 3.4 Hz, 1 H), 3.30 (dd, J = 18.4, 9.4 Hz, 1 H), 4.61–4.68 (m, 1 H), 4.73–4.80 (m, 1 H), 7.51 (t, J = 7.7 Hz, 2 H), 7.57–7.65 (m, 1 H), 8.03 (d, J = 7.7 Hz, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 13.9, 22.2, 26.7, 28.3, 29.0, 34.9, 44.3, 44.6, 87.8, 128.9, 129.2, 134.1, 135.6, 198.5, 213.1. MS (EI, 70 eV): m/z = 276, 229, 105 (100), 77, 57. Anal. Calcd for C₁₉H₂₇NO₄ (333.43): C, 68.44; H, 8.16; N, 4.20. Found: C, 68.50; H, 8.18; N, 4.17.Methyl 7-(2-Naphthoyl)-9-(4-methoxyphenyl)-6-nitro-9-oxononanoate (3dd)Obtained as a mixture of diastereomers (dr = 70:30).Major diastereomer: yellow viscous oil. IR (neat): 1360, 1548, 1598, 1670, 1732 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.19–1.37 (m, 2 H), 1.39–1.64 (m, 3 H), 1.97–2.09 (m, 1 H), 2.18 (t, J = 7.3 Hz, 2 H), 3.24 (dd, J = 3.0, 18.0 Hz, 1 H), 3.59 (s, 3 H), 3.84 (s, 3 H), 3.80–3.89 (m, 1 H), 4.77–4.86 (m, 2 H), 6.88 (d, J = 9.0 Hz, 2 H), 7.55–7.67 (m, 2 H), 7.83–7.92 (m, 3 H), 7.95 (d, J = 8.5 Hz, 1 H), 8.05 (d, J = 8.1 Hz, 1 H), 8.11 (dd, J = 1.7, 8.5 Hz, 1 H), 8.71 (s, 1 H). ¹³C NMR (100 MHz, CDCl₃): δ = 24.1, 25.7, 32.1, 33.7, 39.9, 44.5, 51.8, 55.7, 90.2, 114.1, 124.4, 127.2, 128.0, 129.0, 129.1, 129.2, 130.3, 130.8, 131.2, 132.9, 134.5, 136.2, 164.2, 173.6, 195.2, 199.4. MS (EI, 70 eV): m/z = 444, 155, 135 (100), 127, 107, 77. Anal. Calcd for C₂₈H₂₉NO₇ (491.54): C, 68.42; H, 5.95; N, 2.85. Found: C, 68.46; H, 5.98; N, 2.83.Minor diastereomer: yellow viscous oil. IR (neat): 1356, 1549, 1598, 1671, 1731 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.21–1.44 (m, 2 H), 1.47–1.68 (m, 2 H), 1.71–1.83 (m, 1 H), 2.04–2.17 (m, 1 H), 2.26 (t, J = 7.3 Hz, 2 H), 3.31 (dd, J = 18.0, 3.8 Hz, 1 H), 3.62 (s, 3 H), 3.71 (dd, J = 18.0, 8.6 Hz, 1 H), 3.85 (s, 3 H), 4.92–4.98 (m, 1 H), 5.02–5.08 (m, 1 H), 6.91 (d, J = 9.0 Hz, 2 H), 7.54–7.65 (m, 2 H), 7.86–7.95 (m, 4 H) 8.02 (d, J = 8.1 Hz, 1 H), 8.08 (dd, J = 8.5, 1.8 Hz, 1 H), 8.67 (s, 1 H). ¹³C NMR (100 MHz, CDCl₃): δ = 24.4, 25.7, 29.4, 33.7, 36.7, 44.5, 51.8, 55.8, 87.9, 114.1, 124.3, 127.2, 128.0, 129.1, 129.2, 130.2, 130.7, 131.0, 132.7, 132.8, 136.2, 164.2, 173.8, 195.0, 198.3. MS (EI, 70 eV): m/z = 444, 155, 135 (100), 127, 77. Anal. Calcd for C₂₈H₂₉NO₇ (491.54): C, 68.42; H, 5.95; N, 2.85. Found: 68.47; H, 5.99; N, 2.82. 1-(4-Fluorophenyl)-2-(1-nitropent-4-en-1-yl)-4-(p-tolyl)-butane-1,4-dione (3ee)Obtained as a mixture of diastereomers (dr = 60:40).Major diastereomer: yellow viscous oil. IR (neat): 1358, 1551, 1599, 1672, 1734 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.53–1.68 (m, 1 H), 1.89–2.15 (m, 2 H), 2.30–2.44 (m, 1 H), 2.38 (s, 3 H), 3.21 (dd, J = 18.0, 3.1 Hz, 1 H), 3.82 (dd, J = 18.0, 10.2 Hz, 1 H), 4.57–4.64 (m, 1 H), 4.73–4.80 (m, 1 H), 4.93–5.02 (m, 2 H), 5.54–5.67 (m, 1 H), 7.14–7.30 (m, 4 H), 7.77 (d, J = 8.2 Hz, 2 H), 8.11–8.19 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 21.9, 30.1, 31.4, 40.0, 44.3, 89.3, 116.3, 116.5, 117.3, 128.5, 129.6, 131.8, 131.9, 132.6, 132.7, 133.3, 135.3, 145.0, 165.1, 167.7, 196.4, 197.8. MS (EI, 70 eV): m/z = 337, 253, 213, 123 (100), 119, 95, 91, 65. Anal. Calcd for C₂₂H₂₂FNO₄ (383.42): C, 68.92; H, 5.78; N, 3.65. Found: 68.96; H, 5.81; N, 3.62.Minor diastereomer: yellow viscous oil. IR (neat): 1355, 1548, 1599, 1672, 1730 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.73–1.84 (m, 1 H), 1.92–2.04 (m, 1 H), 2.09–2.26 (m, 2 H), 2.41 (s, 3 H), 3.27 (dd, J = 18.1, 3.9 Hz, 1 H), 3.70 (dd, J = 18.0, 9.0 Hz, 1 H), 4.78–4.91 (m, 2 H), 4.94–5.04 (m, 2 H), 5.57–5.70 (m, 1 H), 7.16–7.28 (m, 4 H), 7.83 (d, J = 8.2 Hz, 2 H), 8.09–8.16 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 21.8, 30.0, 31.3, 39.8, 44.4, 89.3, 116.0, 116.5, 117.1, 128.5, 129.5, 131.6, 131.8, 132.1, 132.3, 133.5, 135.3, 144.9, 165.2, 167.7, 196.3, 197.7. MS (EI, 70 eV): m/z = 337, 253, 213, 123 (100), 119, 95, 91, 65. Anal. Calcd for C₂₂H₂₂FNO₄ (383.42): C, 68.92; H, 5.78; N, 3.65. Found: 68.94; H, 5.76; N, 3.68.4-(Naphthalen-2-yl)-2-(1-nitrohexyl)-1-phenylbutane-1,4-dione (3ff)Obtained as a mixture of diastereomers (dr = 75:25).Major diastereomer: yellow viscous oil. IR (neat): 1362, 1549, 1597, 1672, 1734 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.82 (t, J = 6.9 Hz, 3 H), 1.08–1.38 (m, 6 H), 1.49–1.63 (m, 1 H), 1.94–2.08 (m, 1 H), 3.39 (dd, J = 3.4, 18.0 Hz, 1 H), 4.00 (dd, J = 9.8, 18.0 Hz, 1 H), 4.69–4.76 (m, 1 H), 4.78–4.86 (m, 1 H), 7.51–7.70 (m, 5 H), 7.81–8.00 (m, 4 H), 8.13–8.17 (m, 2 H), 8.44 (s, 1 H). ¹³C NMR (100 MHz, CDCl₃): δ = 13.9, 22.4, 25.8, 30.9, 32.4, 39.9, 44.5, 90.2, 123.8, 127.1, 128.0, 128.8, 128.9, 129.0, 129.1, 129.9, 130.3, 132.6, 133.3, 134.0, 136.0, 137.3, 196.7, 199.4. MS (EI, 70 eV): m/z = 370, 265, 155 (100), 127, 105, 77. Anal. Calcd for C₂₆H₂₇NO₄ (417.51): C, 74.80; H, 6.52; N, 3.35. Found: C, 74.86; H, 6.55; N, 3.32.Major diastereomer: yellow viscous oil. IR (neat): 1355, 1551, 1599, 1674, 1731 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.78–0.90 (m, 3 H), 1.12–1.42 (m, 6 H), 1.63–1.80 (m, 1 H), 2.03–2.22 (m, 1 H), 3.46 (dd, J = 3.4, 18.0 Hz, 1 H), 3.90 (dd, J = 8.5, 18.0 Hz, 1 H), 4.87–5.00 (m, 2 H), 7.50–7.69 (m, 5 H), 7.85–7.92 (m, 2 H), 7.94–8.00 (m, 2 H), 8.13 (d, J = 8.5 Hz, 2 H), 8.49 (s, 1 H).). ¹³C NMR (100 MHz, CDCl₃): δ = 14.1, 22.5, 25.9, 29.5, 31.3, 36.8, 44.7, 88.0, 123.8, 127.2, 128.1, 128.9, 129.0, 129.1, 129.3, 129.9, 130.3, 132.6, 133.5, 134.2, 196.7, 198.3. MS (EI, 70 eV): m/z = 370, 265, 155 (100), 127, 105, 77. Anal. Calcd for C₂₆H₂₇NO₄ (417.51): C, 74.80; H, 6.52; N, 3.35. Found: C, 74.83; H, 6.49; N, 3.33.1-(Naphthalen-2-yl)-2-(1-nitropentyl)-4-(p-tolyl)butane-1,4-dione (3ge)Obtained as a mixture of diastereomers (dr = 70:30).Major diastereomer: yellow viscous oil. IR (neat): 1361, 1548, 1597, 1672, 1733 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.77 (t, J = 7.3 Hz, 3 H), 1.10–1.31 (m, 4 H), 1.52–1.63 (m, 1 H), 1.95–2.08 (m, 1 H), 2.39 (s, 3 H), 3.27 (dd, J = 18.0, 3.4 Hz, 1 H), 3.89 (dd, J = 18.0, 9.4 Hz, 1 H), 4.76–4.88 (m, 2 H), 7.22 (d, J = 8.1 Hz, 2 H), 7.55–7.68 (m, 2 H), 7.79 (d, J = 8.1 Hz, 2 H), 7.88–7.99 (m, 2 H), 8.06 (d, J = 8.5 Hz, 1 H), 8.13 (dd, J = 8.5, 1.7 Hz, 1 H), 8.72 (s, 1 H). ¹³C NMR (100 MHz, CDCl₃): δ = 13.9, 21.9, 22.0, 28.2, 32.2, 40.1, 44.5, 90.4, 124.4, 127.2, 128.0, 128.5, 129.1, 129.2, 129.6, 130.3, 131.2, 132.9, 133.4, 134.6, 136.2, 144.9, 196.5, 199.5. MS (EI, 70 eV): m/z = 370, 251, 155, 127, 119 (100), 91. Anal. Calcd for C₂₆H₂₇NO₄ (417.51): C, 74.80; H, 6.52; N, 3.35. Found: C, 74.76; H, 6.54; N, 3.38.Minor diastereomer: yellow viscous oil. IR (neat): 1357, 1552, 1599, 1674, 1729 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.84 (t, J = 7.3 Hz, 3 H), 1.16–1.39 (m, 4 H), 1.68–1.81 (m, 1 H), 2.02–2.17 (m, 1 H), 2.41 (s, 3 H), 3.35 (dd, J = 18.0, 3.8 Hz, 1 H), 3.78 (dd, J = 18.0, 9.1 Hz, 1 H), 4.92–4.98 (m, 1 H), 5.02–5.09 (m, 1 H), 7.25 (d, J = 8.1 Hz, 2 H), 7.54–7.68 (m, 2 H), 7.81–7.98 (m, 4 H), 8.04 (d, J = 8.5 Hz, 1 H), 8.09 (dd, J = 8.5, 1.7 Hz, 1 H), 8.69 (s, 1 H). ¹³C NMR (100 MHz, CDCl₃): δ = 13.9, 22.0, 22.3, 28.3, 29.3, 36.8, 44.7, 88.1, 124.4, 127.2, 128.0, 128.5, 129.1, 129.2, 129.6, 130.2, 131.0, 132.8, 132.9, 133.7, 136.2, 144.9, 196.4, 198.3. MS (EI, 70 eV): m/z = 370, 251, 155, 127, 119 (100), 91. Anal. Calcd for C₂₆H₂₇NO₄ (417.51): C, 74.80; H, 6.52; N, 3.35. Found: C, 74.78; H, 6.50; N, 3.32.2-[1-(4-Methoxyphenyl)-3-nitro-1-oxo-5-phenylpentan-2-yl]cyclohexan-1-one (3bg)Obtained as a mixture of diastereomers (dr = 50:23:17:10).Major diastereomer: white solid; mp 115–119 °C. IR (Nujol): 1357, 1552, 1600, 1673, 1710 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.45–1.67 (m, 3 H), 1.80–1.92 (m, 2 H), 1.97–2.06 (m, 1 H), 2.14–2.39 (m, 4 H), 2.44–2.72 (m, 3 H), 3.87 (s, 3 H), 4.74 (dd, J = 9.4, 5.1 Hz, 1 H), 4.90–4.97 (m, 1 H), 6.94 (d, J = 9.0 Hz, 2 H), 7.01–7.05 (m, 2 H), 7.14–7.26 (m, 3 H), 8.03 (d, J = 9.0 Hz, 2 H,). ¹³C NMR (100 MHz, CDCl₃): δ = 25.7, 27.8, 31.0, 32.4, 33.6, 42.2, 45.7, 52.4, 55.8, 88.8, 114.2, 126.7, 128.6, 128.8, 131.2, 131.6, 139.6, 164.4, 197.6, 209.9. MS (EI, 70 eV): m/z = 362, 344, 135 (100), 91, 77. Anal. Calcd for C₂₄H₂₇NO₅ (409.48): C, 70.40; H, 6.65; N, 3.42. Found: C, 70.44; H, 6.68; N, 3.40.Mixture of minor diastereomers (45:35:20): yellow viscous oil. IR (neat): 1358, 1553, 1601, 1674, 1711 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 1.01–3.04 (m, 13 H), 3.86 (s, 0.6 H), 3.87 (s, 1.05 H), 3.88 (s, 1.35 H), 4.62–4.83 (m, 1.55 H), 4.94–5.01 (m, 0.45 H), 6.90–6.95 (m, 2 H), 7.05–7.33 (m, 5 H), 7.85–8.03 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 25.2, 25.3, 25.7, 27.0, 27.3, 28.5, 28.6, 29.6, 29.9, 31.3, 32.2, 32.3, 32.4, 32.6, 32.8, 33.4, 41.9, 42.0, 42.7, 45.5, 46.0, 46.8, 50.5, 50.7, 52.8, 55.7, 55.8, 84.7, 86.8, 87.0, 114.2, 114.3, 114.4, 126.7, 126.8, 128.4, 128.7, 128.8, 128.9, 130.8, 130.9, 131.2, 131.4, 139.8, 139.9, 140.0, 164.1, 164.2, 164.4, 197.2, 197.8, 209.5, 209.6, 210.8. MS (EI, 70 eV): m/z = 362, 344, 135 (100), 91, 77. Anal. Calcd for C₂₄H₂₇NO₅ (409.48): C, 70.40; H, 6.65; N, 3.42. Found: C, 70.37; H, 6.61; N, 3.43.Methyl 3-Benzoyl-2,2-dimethyl-4-nitrohexanoate (3ah)Obtained as a mixture of diastereomers (dr = 60:40)Major diastereomer: yellow oil. IR (neat): 1370, 1549, 1675, 1736 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.85 (t, J = 7.3 Hz, 3 H), 1.23 (s, 3 H), 1.35 (s, 3 H), 1.49–1.87 (m, 2 H), 3.62 (s, 3 H), 4.70 (d, J = 9.2 Hz, 1 H), 4.95–5.09 (m, 1 H), 7.48–7.70 (m, 3 H), 8.03–8.12 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 10.6, 22.1, 24.7, 26.7, 45.3, 52.3, 53.0, 89.3, 128.9, 129.2, 134.1, 138.6, 176.1, 199.2. MS (EI, 70 eV): m/z = 261, 229, 201, 161, 105 (100), 77. Anal. Calcd for C₁₆H₂₁NO₅ (307.35): C, 62.53; H, 6.89; N, 4.56. Found: C, 62.60; H, 6.93; N, 4.53.Minor diastereomer: yellow oil. IR (neat): 1372, 1551, 1676, 1731 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.97 (t, J = 7.3 Hz, 3 H), 1.06 (s, 3 H), 1.31 (s, 3 H), 1.73–1.94 (m, 2 H), 3.78 (s, 3 H), 4.95–5.16 (m, 2 H), 7.40–7.66 (m, 3 H), 8.01–8.11 (m, 2 H). ¹³C NMR (100 MHz, CDCl₃): δ = 10.1, 19.0, 24.8, 27.8, 44.9, 50.6, 52.7, 90.5, 128.8, 128.9, 133.8, 138.5, 177.0, 199.6. MS (EI, 70 eV): m/z = 261, 229, 105 (100), 77. Anal. Calcd for C₁₆H₂₁NO₅ (307.35): C, 62.53; H, 6.89; N, 4.56. Found: 62.58; H, 6.87; N, 4.58.Methyl 3-(2-Naphthoyl)-2,2-dimethyl-4-nitrooctanoate (3gh)Obtained as a mixture of diastereomers (dr = 60:40)Major diastereomer: yellow oil. IR (neat): 1369, 1550, 1673, 1733 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.77 (t, J = 7.0 Hz, 3 H), 1.05–1.35 (m, 4 H), 1.26 (s, 3 H), 1.40 (s, 3 H), 1.46–1.65 (m, 1 H), 1.70–1.95 (m, 1 H), 3.64 (s, 3 H), 4.86 (d, J = 9.1 Hz, 1 H), 5.09–5.25 (m, 1 H), 7.56–7.74 (m, 2 H), 7.89–8.00 (m, 2 H), 8.05–8.14 (m, 2 H), 8.62 (s, 1 H). ¹³C NMR (100 MHz, CDCl₃): δ = 13.7, 21.8, 21.9, 25.0, 28.2, 33.0, 45.4, 52.4, 53.2, 87.9, 124.0, 127.4, 128.0, 129.2, 129.4, 130.2, 131.2, 132.7, 135.9, 136.1, 176.2, 199.1. MS (EI, 70 eV): m/z = 385, 307, 155 (100), 127. Anal. Calcd for C₂₂H₂₇NO₅ (385.46): C, 68.55; H, 7.06; N, 3.63. Found: C, 68.51; H, 7.08; N, 3.65.Minor diastereomer: yellow oil. IR (neat): 1357, 1551, 1674, 1730 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 0.91 (t, J = 7.3 Hz, 3 H), 1.07 (s, 3 H), 1.22–1.45 (m, 4 H), 1.34 (s, 3 H), 1.69–1.91 (m, 2 H), 3.79 (s, 3 H), 5.07–5.25 (m, 2 H), 7.51–7.66 (m, 2 H), 7.85–7.94 (m, 2 H), 8.01–8.09 (m, 2 H), 8.60 (s, 1 H). ¹³C NMR (100 MHz, CDCl₃): δ = 14.0, 18.9, 22.2, 27.7, 28.1, 31.2, 44.0, 51.0, 53.0, 89.3, 124.2, 127.2, 128.0, 129.0, 129.2, 130.2, 131.1, 132.7, 135.7, 136.1, 177.3, 199.7. MS (EI, 70 eV): m/z = 385, 307, 155 (100), 127. Anal. Calcd for C₂₂H₂₇NO₅ (385.46): C, 68.55; H, 7.06; N, 3.63. Found: C, 68.57; H, 7.03; N, 3.61.
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• 10b Ono N. The Nitro Group in Organic Synthesis. Wiley; New York: 2001
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