Synlett 2006(20): 3419-3422  
DOI: 10.1055/s-2006-956466
LETTER
© Georg Thieme Verlag Stuttgart · New York

Aza-Mannich Condensation of Sulfinimine Promoted by Tetrabutyl­ammonium Fluoride: Synthesis of α,β-Unsaturated Sulfinimine

Xiaoxia Bian, Dan Zhang, Zhiyan Huang, Yong Qin*
Department of Chemistry of Medicinal Natural Products and Key Laboratory of Drug Targeting, West China School of Pharmacy and State Key Laboratory of Biotherapy, Sichuan University, Chengdu 610041, P. R. of China
e-Mail: yongqin@scu.edu.cn;
Further Information

Publication History

Received 12 July 2006
Publication Date:
08 December 2006 (online)

Abstract

Self-condensation of tert-butanesulfinimine 5 was realized in the presence of tetrabutylammonium fluoride to afford α,β-unsaturated sulfinimine 8 in moderate to high yields with high geometric selectivities. The synthesized α,β-unsaturated sulfinimine 8 was demonstrated to be a versatile intermediate for the syntheses of enal 4 and chiral allyl amine 11.

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Representative Procedure of Self-Condensation: To a solution of 5 (1 mmol) in anhyd Et2O (10 mL) was added anhyd TBAF (1.2 mmol, dried by P2O5 in vacuum condition). The biphasic mixture was stirred at r.t. for 30 min and then diluted with Et2O (30 mL). After washing of the mixture with sat. NaCl solution, the solvent was evaporated to give a residue. The residue was either subjected to chromatography to give α,β-unsaturated sulfinimine 8 and tert-butanesulfinamide 9, or was subjected to hydrolysis to give enal 4.
Data for 8a (major isomer): 1H NMR (400 MHz, CDCl3): δ = 0.85-0.91 (m, 6 H), 1.21 (s, 9 H), 1.23-1.50 (m, 18 H), 2.28 (q, J = 6.4 Hz, 2 H), 2.31-2.46 (m, 2 H), 6.20 (t, J = 7.6 Hz, 1 H), 8.05 (s, 1 H). 13C NMR (100 MHz, CDCl3): δ = 14.0, 22.4, 22.5, 22.6, 25.8, 28.7, 28.8, 28.9, 29.0, 29.3, 29.4, 29.7, 31.6, 31.7, 57.1, 139.5, 148.8, 166.3. HRMS: m/z [M + H+] calcd for C20H40NOS: 342.2825; found: 342.2813.
Data for 8b (major isomer): 1H NMR (400 MHz, CDCl3): δ = 0.95 (t, J = 7.2 Hz, 3 H), 1.01 (t, J = 7.6 Hz, 3 H), 1.20 (s, 9 H), 1.47 (q, J = 7.2 Hz, 2 H), 2.27 (q, J = 7.6 Hz, 2 H), 2.32-2.48 (m, 2 H), 6.18 (t, J = 7.6 Hz, 1 H), 8.04 (s, 1 H). 13C NMR (50 MHz, CDCl3): δ = 13.5, 13.7, 19.1, 22.5, 29.7, 30.6, 57.1, 141.0, 148.1, 166.0. HRMS: m/z [M + Na+] calcd for C12H23NNaOS: 252.1393; found: 252.1397.
Data for (S)-8c: [a]20 D +131.9 (c = 1.0, CHC13). 1H NMR (400 MHz, CDCl3): δ = 0.98 (s, 9 H), 2.68-2.81 (m, 4 H), 3.72 (dd, J 1 = 27.6 Hz, J 2 = 14.8 Hz, 2 H), 6.45 (t, J = 6.8 Hz, 1 H), 7.05-7.31 (m, 10 H), 8.10 (s, 1 H). 13C NMR (100 MHz, CDCl): δ = 22.2, 31.0, 31.6, 34.8, 57.1, 125.9, 126.2, 128.1, 128.2, 128.4, 128.5, 138.3, 139.3, 140.6, 148.2, 165.4. HRMS: m/z [M + Na+] calcd for C22H27NNaOS: 376.1706; found: 376.1704.
Data for 8d (major isomer): 1H NMR (400 MHz, CDCl3): δ = 1.20 (s, 9 H), 1.78-1.87 (m, 2 H), 2.03 (s, 3 H), 2.07 (s, 3 H), 2.40-2.46 (m, 2 H), 2.70-2.80 (m, 2 H), 4.05-4.18 (m, 4 H), 6.34 (t, J = 7.6 Hz, 1 H), 8.10 (s, 1 H). 13C NMR (50 MHz, CDCl3): δ = 20.9, 22.5, 24.2, 25.5, 27.9, 29.7, 57.3, 62.6, 63.6, 135.5, 149.1, 165.5, 170.7, 171.1. HRMS: m/z [M + H+] calcd for C16H28NO5S: 346.1682; found: 346.1685.
Data for 8e (major isomer): 1H NMR (400 MHz, CDCl3): δ = 1.15 (s, 9 H), 1.72-1.82 (m, 2 H), 2.42-2.50 (m, 2 H), 2.70-2.84 (m, 2 H), 3.44-3.54 (m, 4 H), 4.47 (s, 2 H), 4.48 (s, 2 H), 6.30 (t, J = 7.6 Hz, 1 H), 7.24-7.38 (m, 10 H), 8.06 (s, 1 H). 13C NMR (50 MHz, CDCl3): δ = 22.4, 25.8, 26.5, 26.7, 57.0, 68.4, 69.2, 72.5, 72.6, 127.4, 127.5, 126.2, 126.3, 135.7, 138.3, 149.8, 165.7. HRMS: m/z [M + H+] calcd for C26H36NOS: 442.2410; found: 442.2422.
Data for 4g (major isomer): 1H NMR (400 MHz, CDCl3): δ = 1.55-1.70 (m, 6 H), 2.30-2.42 (m, 4 H), 3.42-3.51 (m, 4 H), 4.48 (s, 2 H), 4.49 (s, 2 H), 6.47 (t, J = 7.6 Hz, 1 H), 7.25-7.36 (m, 10 H), 9.36 (s, 1 H). 13C NMR (50 MHz, CDCl3): δ = 20.7, 25.4, 26.5, 26.6, 26.7, 29.4, 69.7, 69.8, 72.8, 72.9, 127.4, 127.5, 127.6, 128.3, 128.4, 138.4, 138.5, 143.2, 155.3, 195.1. HRMS: m/z [M + Na+] calcd for C24H30NaO3: 389.2087; found: 389.2089.
Data for 4h (major isomer): 1H NMR (400 MHz, CDCl3): δ = 1.38-1.57 (m, 6 H), 1.57-1.70 (m, 4 H), 2.25 (t, J = 7.6 Hz, 2 H), 2.34 (q, J = 7.2 Hz, 2 H), 3.42-3.50 (m, 4 H), 4.48 (s, 2 H), 4.50 (s, 2 H), 6.43 (t, J = 7.6 Hz, 1 H), 7.24-7.38 (m, 10 H), 9.35 (s, 1 H). 13C NMR (50 MHz, CDCl3): δ = 23.7, 25.3, 26.0, 28.5, 28.7, 29.5, 29.6, 70.1, 72.8, 76.4, 77.0, 77.7, 127.4, 127.5, 127.6, 128.3, 128.4, 138.3, 138.4, 143.5, 155.3, 195.2. HRMS: m/z [M + Na+] calcd for C26H34NaO3: 417.2400; found: 417.2388.
Data for 10 (Z major isomer): 1H NMR (400 MHz, CDCl3): δ = 0.98 (s, 9 H), 4.06 (dd, J 1 = 19.6 Hz, J 2 = 15.2 Hz, 2 H), 7.14-7.31 (m, 5 H), 7.41 (s, 1 H), 7.57 (d, J = 8.8 Hz, 2 H), 8.21 (d, J = 9.2 Hz, 2 H), 8.36 (s, 1 H). 13C NMR (100 MHz, CDCl3): δ = 22.3, 32.6, 57.8, 123.9, 126.4, 127.9, 128.7, 129.9, 138.2, 140.3, 141.6, 142.2, 147.6, 165.0. HRMS: m/z [M + Na+] calcd for C20H22N2NaO3S: 393.1243; found: 393.1235. Data for 10 (E minor isomer): 1H NMR (400 MHz, CDCl3): δ = 0.98 (s, 9 H), 4.16 (dd, J 1 = 24.8 Hz, J 2 = 16.4 Hz, 2 H), 7.35 (d, J = 8.4 Hz, 2 H), 7.38-7.42 (m, 5 H), 7.46 (s, 1 H), 8.14 (d, J = 8.8 Hz, 2 H), 8.36 (s, 1 H).

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Representative Procedure of Grignard Addition to 8c: To a solution of 8c (1 mmol) in anhyd CH2Cl2 (10 mL) at 0 °C was added Grignard reagent (3 equiv). After being stirred for 1-5 h, the mixture was poured into sat. NH4Cl solution, and the solution was extracted with CH2Cl2. The combined organic phases were dried with Na2SO4. After removing the solvent, the residue was subjected to chromatography to give allyl amine 11. The dr was determined by 1H NMR analysis of crude 11. The absolute configuration of amine in 11 was not determined due to lack of comparable rotation data of structurally similar chiral amine.
Data for 11a (major isomer): [α]20 D +11.9 (c = 1.0, CHC13). 1H NMR (400 MHz, CDCl3): δ = 1.14 (s, 9 H), 2.32 (s, 3 H), 2.43-2.50 (m, 2 H), 2.71 (t, J = 7.6 Hz, 2 H), 3.10 (d, J = 15.6 Hz, 1 H), 3.26 (d, J = 4.0 Hz, 1 H), 3.40 (d, J = 15.6 Hz, 1 H), 4.82 (d, J = 4.0 Hz, 1 H), 5.89 (t, J = 7.2 Hz, 1 H), 6.94 (d, J = 6.8 Hz, 2 H), 7.09-7.30 (m, 12 H). 13C NMR (50 MHz, CDCl3): δ = 21.1, 22.6, 30.0, 34.1, 35.7, 55.7, 63.1, 125.7, 125.9, 127.5, 128.3, 128.3, 128.5, 129.2, 129.5, 137.4, 137.8, 138.1, 139.3, 141.6. HRMS: m/z [M + H+] calcd for C29H36NOS: 446.2512; found: 446.2521.
Date for 11b (major isomer): [α]20 D +33.5 (c = 1.0, CHC13). 1H NMR (400 MHz, CDCl3): δ = 1.15 (s, 9 H), 1.28 (s, 3 H), 2.42-2.48 (m, 2 H), 2.73 (t, J = 7.6 Hz, 2 H), 2.91 (d, J = 5.6 Hz, 1 H), 3.41 (dd, J 1 = 23.2 Hz, J 2 = 15.6 Hz, 2 H), 3.88 (m, 1 H), 5.73 (t, J = 7.6 Hz, 1 H), 7.08 (d, J = 7.2 Hz, 2 H), 7.16-7.35 (m, 8 H). 13C NMR (50 MHz, CDCl3): δ = 22.4, 22.6, 30.2, 33.4, 35.7, 55.5, 56.8, 125.9, 126.0, 128.3, 128.4, 128.5, 139.1, 139.7, 141.7. HRMS: m/z [M + H+] calcd for C23H32NOS: 370.2199; found: 370.2210.
Date for 11c (major isomer): [α]20 D +34.0 (c = 1.0, CHC13). 1H NMR (400 MHz, CDCl3): δ = 0.77 (d, J = 6.8 Hz, 3 H), 0.90 (d, J = 6.8 Hz, 3 H), 1.07 (s, 9 H), 1.70-1.74 (m, 1 H), 2.44-2.50 (m, 2 H), 2.68-2.72 (m, 2 H), 3.12 (d, J = 3.6 Hz, 1 H), 3.31-3.41 (m, 2 H), 3.43-3.44 (m, 1 H), 5.63 (t, J = 7.2 Hz, 1 H), 7.10-7.28 (m, 10 H). 13C NMR (100 MHz, CDCl3): δ = 18.6, 20.0, 22.3, 30.2, 30.9, 33.7, 35.6, 55.2, 67.3, 76.5, 76.8, 77.2, 125.7, 125.8, 128.1, 128.3, 128.5, 130.7, 136.5, 139.4, 141.5. HRMS: m/z [M + Na+] calcd for C25H35NNaOS: 420.2332; found: 420.2337.
Date for 11d (major isomer): [α]20 D +15.3 (c = 1.0, CHC13). 1H NMR (400 MHz, CDCl3): δ = 0.92 (s, 9 H), 1.07 (s, 9 H), 2.32-2.42 (m, 2 H), 2.65 (t, J = 8.0 Hz, 2 H), 3.24-3.28 (m, 2 H), 3.56-3.60 (m, 2 H), 5.63 (t, J = 7.2 Hz, 1 H), 7.10 (d, J = 6.8 Hz, 2 H), 7.14-7.30 (m, 8 H). 13C NMR (100 MHz, CDCl3): δ = 22.3, 27.2, 29.5, 30.4, 35.4, 36.0, 55.2, 68.1, 125.6, 128.0, 128.1, 128.2, 128.6, 132.4, 139.1, 141.5. HRMS: [M + H+] calcd for C26H38NOS: 412.2669; found: 412.2653.