A Novel Prins Bicyclization Strategy for the Synthesis of Sugar Annulated Furopyran Scaffolds

Abstract

A tandem Prins bicyclization of sugar-derived homo­allylic diols with aldehydes has been accomplished using 10 mol% of In(OTf)₃ and 20 mol% of TsOH at ambient temperature to produce a novel series of sugar-annulated furopyran derivatives in good yields with high selectivity. This is the first report on Prins bicyclization of homoallylic diols derived from sugars. The cooperative catalysis between In(OTf)₃ and TsOH provides high conversions and enhanced reaction rates.

Key words

Prins bicyclization - d-glucose - sugar-annulated ­heterocycles - metal triflate - cooperative catalysis

• References and Notes

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• 10 General Procedure: To a stirred solution of homoallylic diol (1a; 100 mg, 0.37 mmol) in the presence of 4 Å MS were added aldehyde (2, 0.44 mmol), followed by In(OTf)₃ (10 mol%) and TsOH (20 mol%) in anhyd DCE (5 mL) at 0 °C. The resulting mixture was stirred at r.t. under a nitrogen atmosphere for the specified time (Table ). After completion of the reaction as indicated by TLC, the mixture was quenched with sat. aq NaHCO₃ solution (0.5 mL) and extracted with CH₂Cl₂ (2 × 10 mL). The combined organic phases were washed with brine (3 × 2 mL), dried over anhyd Na₂SO₄ and concentrated in vacuo. The crude product was purified by silica gel column chromatography (60–120 mesh) using EtOAc–hexane (3:7) as eluent to afford the pure product 3. (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-Phenyloctahydro-3aH-spiro([1,3]dioxolo[4′′,5′′:4′,5′]furo[2′,3′:4,5]furo-[3,2-c]pyran-2,1′-cyclohexane) (3a): viscous liquid; [α]_D ²⁵ +16.9 (c 0.5, CHCl₃). ¹H NMR (500 MHz, CDCl₃): δ = 1.47–1.65 (m, 10 H), 1.85–1.94 (m, 2 H), 2.39–2.46 (m, 1 H), 3.45–3.53 (m, 1 H), 4.16–4.21 (m, 1 H), 4.35 (d, J = 3.1 Hz, 1 H), 4.39 (t, J = 3.1 Hz, 1 H), 4.45 (dd, J = 7.9, 9.5 Hz, 1 H), 4.55 (d, J = 3.1 Hz, 1 H), 4.71 (d, J = 4.7 Hz, 1 H), 6.03 (d, J = 3.9 Hz, 2 H), 7.25–7.31 (m, 1 H), 7.36 (t, J = 7.1 Hz, 2 H), 7.51 (d, J = 7.9 Hz, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.5, 23.7, 24.8, 31.9, 31.4, 36.6, 36.1, 47.6, 65.5, 77.2, 78.3, 82.8, 83.5, 87.6, 107.0, 126.3, 127.5, 128.3. IR (neat): 3430, 2927, 2854, 1731, 1074, 804, 701 cm^–1. ESI–MS: m/z = 359. HRMS (ESI): m/z [M + Na]⁺ calcd for C₂₁H₂₆O₅: 381.1672; found: 381.1676. (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-(m-Tolyl)octahydro-3aH-spiro([1,3]dioxolo[4′′,5′′:4′,5′]furo [2′,3′:4,5]furo-[3,2-c]pyran-2,1′-cyclohexane) (3b): viscous liquid; [α]_D ²⁵ +35.5 (c 0.25, CHCl₃). ¹H NMR (300 MHz, CDCl₃): δ = 1.40–1.70 (m, 10 H), 1.84–1.95 (m, 2 H), 2.34–2.38 (s, 3 H), 2.39–2.46 (m, 1 H), 3.43–3.46 (m, 1 H), 4.15–4.23 (m, 1 H), 4.36 (d, J = 3.0 Hz, 1 H), 4.41–4.49 (m, 2 H), 4.57 (d, J = 3.7 Hz, 1 H), 4.68 (d, J = 4.5 Hz, 1 H), 6.05 (d, J = 3.7 Hz, 1 H), 7.10 (d, J = 6.7 Hz, 1 H), 7.25–7.43 (m, 3 H). ¹³C NMR (75 MHz, CDCl₃): δ = 21.4, 23.6, 23.8, 24.8, 31.5, 31.9, 36.3, 36.6, 47.6, 65.6, 77.2, 78.4, 82.8, 83.5, 87.5, 107.0, 123.4, 127.1, 128.1, 128.2. IR (neat): 3434, 2929, 2854, 1734, 1454, 1109, 772 cm^–1. ESI–MS: m/z = 373 [M + H]⁺. HRMS (ESI): m/z [M + Na]⁺ calcd for C₂₂H₂₈O₅: 395.1829; found: 395.1831. (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-Phenyloctahydro-3aH-spiro([1,3]dioxolo[4′′,5′′:4′,5′]furo[2′,3′:4,5]furo-[3,2-c]pyran-2,1′-cyclohexane) (3c): viscous liquid; [α]_D ²⁵ +22 (c 0.3, CHCl₃). ¹H NMR (500 MHz, CDCl₃): δ = 1.30–1.61 (m, 10 H), 1.88–1.91 (m, 2 H), 2.40 (m, 1 H), 3.46–3.52 (m, 1 H), 3.84 (s, 3 H), 4.15–4.21 (m, 1 H), 4.35 (d, J = 3.0 Hz, 1 H), 4.40–4.46 (m, 2 H), 4.58 (d, J = 4.0 Hz, 1 H), 4.68 (d, J = 4.0 Hz, 1 H), 6.04 (d, J = 4.0 Hz, 1 H), 6.85 (dd, J = 3.0, 9.0 Hz, 1 H), 7.00 (d, J = 8.0 Hz, 1 H), 7.23–7.28 (m, 2 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.6, 23.8, 24.8, 36.2, 36.7, 47.5, 55.3, 65.6, 77.2, 78.5, 82.9, 83.5, 87.4, 106.9, 111.2, 112.2, 114.5, 118.8, 129.1, 141.6. IR (neat): 3455, 2930, 2855, 1729, 1603, 1107, 772 cm^–1. ESI–MS: m/z = 389 [M + H]⁺. HRMS (ESI): m/z [M + Na]⁺ calcd for C₂₂H₂₈O₆: 411.1778; found: 411.1767. (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-(4-Methoxy-phenyl)octahydro-3aH-spiro([1,3]dioxolo[4′′,5′′:4′,5′]-furo[2′,3′:4,5]furo[3,2-c]pyran-2,1′-cyclohexane) (3d): viscous liquid; [α]_D ²⁵ +11 (c 0.25, CHCl₃). ¹H NMR (500 MHz, CDCl₃): δ = 1.45–1.65 (m, 10 H), 1.82–1.91 (m, 2 H), 2.35–2.41 (m, 1 H), 3.42–3.52 (m, 1 H), 3.81 (s, 3 H), 4.13–4.20 (m, 1 H), 4.35 (d, J = 2.9 Hz, 1 H), 4.39–4.44 (m, 2 H), 4.57 (d, J = 3.9 Hz, 1 H), 4.66 (d, J = 3.9 Hz, 1 H), 6.04 (d, J = 3.9 Hz, 1 H), 6.90 (d, J = 7.7 Hz, 2 H), 7.45 (d, J = 8.7 Hz, 2 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.6, 23.8, 24.8, 31.9, 36.2, 47.9, 55.2, 65.6, 78.1, 82.9, 83.6, 87.6, 107.0, 112.2, 113.6, 127.7. IR (neat): 2924, 2853, 1735, 1458, 1106, 1070 cm^–1. ESI–MS: m/z = 406 [M + NH₄]⁺. HRMS (ESI): m/z [M + Na]⁺ calcd for C₂₂H₂₈O₆: 411.1778; found: 411.1767. (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-(4-Fluoro-phenyl)octahydro-3aH-spiro([1,3]dioxolo[4′′,5′′:4′,5′]-furo[2′,3′:4,5]furo[3,2-c]pyran-2,1′-cyclohexane) (3e): semi-solid; [α]_D ²⁵ +17 (c 0.5, CHCl₃). ¹H NMR (500 MHz, CDCl₃): δ = 1.45–1.65 (m, 10 H), 1.82–1.93 (m, 2 H), 2.36–2.42 (m, 1 H), 3.44–3.51 (m, 1 H), 4.14–4.20 (m, 1 H), 4.34–4.37 (s, 2 H), 4.43 (dd, J = 7.7, 11.0 Hz, 1 H), 4.57 (d, J = 3.3 Hz, 1 H), 4.69 (d, J = 4.4 Hz, 1 H), 6.02 (d, J = 3.3 Hz, 1 H), 7.05 (t, J = 8.8 Hz, 2 H), 7.50 (dd, J = 3.3, 5.5 Hz, 2 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.6, 23.8, 24.8, 31.4, 36.1, 36.6, 47.7, 65.5, 77.7, 82.7, 83.6, 87.5, 107.0, 112.3, 115.0, 115.1, 128.0, 128.1, 135.9. IR (neat): 3460, 2928, 2854, 1728, 1602, 1102, 800 cm^–1. ESI–MS: m/z = 377 [M + H]⁺. HRMS (ESI): m/z [M + Na]⁺ calcd for C₂₁H₂₅FO₅: 399.1578; found: 399.1574. (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-(4Chlorophenyl)-octahydro-3aH-spiro([1,3]dioxolo[4′′,5′′:4′,5′]-furo[2′,3′:4,5]furo[3,2-c]pyran-2,1′-cyclohexane) (3f): semi-solid; [α]_D ²⁵ +19 (c 0.5, CHCl₃). ¹H NMR (500 MHz, CDCl₃): δ = 1.46–1.60 (m, 10 H), 1.86–1.94 (m, 2 H), 2.37–2.45 (m, 1 H), 3.43–3.53 (m, 1 H), 4.13–4.21 (m, 1 H), 4.34–4.38 (m, 2 H), 4.45 (dd, J = 7.5, 10.5 Hz, 1 H), 4.58 (d, J = 3.7 Hz, 1 H), 4.70 (d, J = 4.5 Hz, 1 H), 6.03 (d, J = 3.7 Hz, 1 H), 7.32–7.38 (m, 2 H), 7.42–7.48 (m, 2 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.6, 23.8, 24.9, 31.4, 36.1, 36.6, 47.5, 65.5, 77.5, 82.7, 83.6, 87.6, 107.0, 112.3, 127.8, 128.4, 138.7. IR (neat): 3782, 3682, 2930, 2855, 1732, 1105, 823 cm^–1. ESI–MS: m/z = 393 [M + H]⁺. HRMS (ESI): m/z [M + Na]⁺ calcd for C₂₁H₂₅ClO₅: 415.1282; found: 415.1275. (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-(4-Bromophenyl)-octahydro-3aH-spiro([1,3]dioxolo[4′′,5′′:4′,5′]-furo[2′,3′:4,5]furo[3,2-c]pyran-2,1′-cyclohexane) (3g): solid; mp 146–148 °C; [α]_D ²⁵ +23.8 (c 0.25, CHCl₃). ¹H NMR (500 MHz, CDCl₃): δ = 1.42–1.66 (m, 10 H), 1.82–1.92 (m, 2 H), 2.35–2.45 (m, 1 H), 3.42–3.54 (m, 1 H), 4.12–4.21 (m, 1 H), 4.33–4.38 (m, 2 H), 4.45 (dd, J = 7.5, 10.5 Hz, 1 H), 4.57 (d, J = 3.8 Hz, 1 H), 4.68 (d, J = 4.5 Hz, 1 H), 6.02 (d, J = 3.8 Hz, 1 H), 7.39 (d, J = 8.3 Hz, 2 H), 7.50 (d, J = 9.0 Hz, 2 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.5, 23.7, 24.8, 31.3, 36.0, 36.6, 47.3, 65.4, 76.8, 77.5, 82.7, 83.5, 87.6, 106.9, 112.3, 121.3, 128.0, 131.3, 139.1. IR (neat): 3451, 2933, 2856, 1631, 1108 cm^–1. ESI–MS: m/z = 454 [M + NH₄]⁺. HRMS (ESI): m/z [M + Na]⁺ calcd for C₂₁H₂₅BrO₅: 459.0777; found: 459.0777.⁺ (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-(Naphthalen-2-yl)octahydro-3aH-spiro([1,3]dioxolo[4′′,5′′:4′,5′]-furo[2′,3′:4,5]furo[3,2-c]pyran-2,1′-cyclohexane) (3h): viscous liquid; [α]_D ²⁵ +9 (c 0.25, CHCl₃). ¹H NMR (500 MHz, CDCl₃): δ = 1.40–1.67 (m, 10 H), 1.87–1.99 (m, 2 H), 2.52–2.58 (m, 1 H), 3.53–3.60 (m, 1 H), 4.22–4.29 (m, 1 H), 4.37 (d, J = 3.0 Hz, 1 H), 4.40 (t, J = 3.0 Hz, 1 H), 4.50 (q, J = 9.0 Hz, 1 H), 4.58 (d, J = 4.0 Hz, 1 H), 4.90 (d, J = 4.0 Hz, 1 H), 6.02 (d, J = 3.0 Hz, 1 H), 7.46–7.51 (m, 2 H), 7.68 (d, J = 7.0 Hz, 1 H), 7.82–7.91 (m, 3 H), 7.97 (s, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.5, 23.7, 24.8, 31.5, 36.1, 36.5, 47.6, 65.6, 77.2, 78.3, 82.8, 83.5, 87.6, 107.0, 113.7, 124.3, 125.1, 125.7, 125.9, 127.6, 128.1, 127.6. IR (neat): 2924, 2852, 1736, 1461, 1219, 772 cm^–1. ESI–MS: m/z = 409 [M + H]⁺. HRMS (ESI): m/z [M + Na]⁺ calcd for C₂₅H₂₈O₅: 431.1829; found: 431.1822. (3aR,4aR,4bS,5R,8aS,9aS,9bR)-5-(4,5a1-Dihydro-pyren1yl)octahydro-3aH-spiro([1,3]dioxolo-[4′′,5′′:4′,5′]furo[2′,3′:4,5]furo[3,2-c]pyran-2,1′-cyclohexane) (3i): semi-solid; [α]_D ²⁵ +194 (c 0.25, CHCl₃). ¹H NMR (300 MHz, CDCl₃): δ = 1.30–1.61 (m, 10 H), 1.98–2.09 (m, 2 H), 2.76–2.86 (m, 1 H), 3.60–3.80 (m, 1 H), 4.03 (t, J = 3.0 Hz, 1 H), 4.26 (d, J = 3.0 Hz, 1 H), 4.31–4.40 (m, 1 H), 4.56 (d, J = 3.7 Hz, 1 H), 4.80 (dd, J = 8.3, 9.0 Hz, 1 H), 5.82 (d, J = 4.5 Hz, 1 H), 6.04 (d, J = 3.7 Hz, 2 H), 7.95–8.04 (m, 1 H), 8.07 (d, J = 3.7 Hz, 1 H), 8.11 (d, J = 1.5 Hz, 2 H), 8.18 (dd, J = 3.0, 4.5 Hz, 2 H), 8.29 (d, J = 8.3 Hz, 1 H), 8.60 (d, J = 7.5 Hz, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.5, 23.6, 24.7, 36.0, 36.6, 46.9, 65.9, 74.6, 76.9, 82.9, 83.4, 87.5, 106.9, 112.2, 121.6, 124.4, 124.9, 125.2, 125.3, 125.4, 125.7, 126.1, 126.9, 127.6, 127.7, 130.3, 130.4, 131.2, 133.6. IR (neat): 3445, 2929, 2854, 1729, 1366, 1106, 846 cm^–1. ESI–MS: m/z = 505 [M + Na]⁺. HRMS (ESI): m/z [M + Na]⁺ calcd for C₃₁H₃₀O₅: 505.1985; found: 505.1982. (3aR,4aR,5R,9aS,9bR)-5-(2-Fluorophenyl)-2,2-dimethyloctahydro-3aH-([1,3]dioxolo[4′′,5′′:4′,5′]furo-[2′,3′:4,5]furo[3,2-c]pyran) (3j): [α]_D ²⁵ +50.2 (c 0.50, CHCl₃). ¹H NMR (500 MHz, CDCl₃): δ = 1.30–1.75 (m, 6 H), 1.80–1.98 (m, 2 H), 2.27–2.38 (m, 2 H), 3.47–3.58 (m, 1 H), 4.13–4.25 (m, 1 H), 4.35 (d, J = 10.8 Hz, 1 H), 4.42–4.50 (m, 1 H), 4.58 (d, J = 2.8 Hz, 1 H), 5.07 (d, J = 2.7 Hz, 1 H), 6.02 (d, J = 3.0 Hz, 1 H), 6.93–7.09 (m, 2 H), 7.18–7.41 (m, 1 H), 7.76–7.86 (m, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 22.7, 26.6, 26.9, 45.7, 62.1, 65.5, 71.4, 83.2, 83.9, 87.4, 107.4, 111.5, 114.3, 114.5, 123.9, 124.4, 124.5, 127.2, 127.3, 128.7, 128.8, 157.9, 159.8. IR (neat): 2925, 2854, 1742, 1492, 1459, 1374, 1222, 1111, 1075, 771 cm^–1. ESI–MS: m/z = 359 [M + Na]⁺. [(Z)-4-Hydroxybut-1-en-1-yl]tetrahydrospiro(cyclo-hexane-1,2′-furo[2,3-d][1,3]dioxol)-6′-ol (1a): [α]_D ²⁵ –22.5 (c 0.5, CHCl₃). ¹H NMR (300 MHz, CDCl₃): δ = 1.35–1.74 (m, 10 H), 2.32–2.52 (m, 2 H), 3.66–3.80 (m, 2 H), 4.20 (d, J = 2.2 Hz, 1 H), 4.57 (d, J = 3.7 Hz, 1 H), 4.95 (dd, J = 2.2, 3.0 Hz, 1 H), 5.60–5.77 (m, 2 H), 5.97 (d, J = 3.7 Hz, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 23.5, 23.9, 24.8, 31.7, 35.8, 36.4, 61.3, 77.2, 78.0, 84.7, 103.9, 112.1, 126.5, 131.2. IR (neat): 3421, 2934, 2858, 1655, 1111, 1069, 1013, 953, 802 cm^–1. ESI–MS: m/z = 293 [M + Na]⁺. HRMS: m/z [M + Na]⁺ calcd for C₁₄H₂₂O₅: 293.1359; found: 293.1353. {(E)-[5-(4-Hydroxy-but-1-enyl)-2,2-dimethyl]tetra-hydrofuro[2,3-d][1,3]dioxol}-6-ol (1b): [α]_D ²⁵ –42.2 (c 0.61, CHCl₃). ¹H NMR (300 MHz, CDCl₃): δ = 1.20–1.33 (m, 6 H), 2.42–2.51 (m, 1 H), 3.61–3.79 (m, 2 H), 4.12 (d, J = 2.6 Hz, 1 H), 4.51 (d, J = 3.7 Hz, 1 H), 4.84–4.91 (m, 1 H), 5.55–5.72 (m, 2 H), 5.89 (d, J = 3.5 Hz, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 26.1, 26.7, 31.6, 61.2, 76.3, 77.9, 85.2, 104.3, 111.4, 126.4, 131.2. IR (neat): 3363, 2978, 2927, 1376, 1248, 1217, 1163, 1071, 1008, 946 cm^–1. ESI–MS: m/z = 230 [M + Na]⁺. HRMS: m/z calcd for C₁₁H₁₈O₅: 253.1044 [M + Na]⁺; found: 253.1046.