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Synlett 2005(2): 294-298  
DOI: 10.1055/s-2004-837214
LETTER
© Georg Thieme Verlag Stuttgart · New York

γ-Allenyl Allyl Benzothiazole Sulfonyl Anions Undergo cis-Selective (Sylvestre) Julia Olefinations

Belén Vaz, Rosana Alvarez, José A. Souto, Angel R. de Lera*
Departamento de Química Orgánica, Universidade de Vigo, 36310 Vigo, Spain
Fax: +34(986)812556; e-Mail: qolera@uvigo.es;
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Publication History

Received 28 October 2004
Publication Date:
17 December 2004 (online)

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Abstract

γ-Allenyl allyl benzothiazolyl sulfones 8 and ent-8 provided allenyl trienes and polyenes with cis-selectivities ranging from 71:29 to 100:0 upon condensation (NaHMDS, THF, -78 °C to 25 ºC) with a variety of unsaturated aldehydes.

Key words

Julia olefination - stereoselectivity - allenes - polyenes

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Vaz, B.; Alvarez, R.; Brückner, R.; de Lera, A. R., submitted.

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All new compounds gave satisfactory spectroscopic data and correct combustion analysis or HRMS.

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Data for 13f: 1H NMR (600 MHz, CDCl3): δ = 9.45 (s, 1 H, CHO), 6.98 (dd, J = 14.4, 11.8 Hz, 1 H, H15), 6.95 (d, J = 11.9 Hz, 1 H, H14 ′), 6.68 (dd, J = 14.4, 11.7 Hz, 1 H, H15 ′), 6.59 (d, J = 12.1 Hz, 1 H, H10), 6.38 (t, J = 12.0 Hz, 1 H, H11), 6.33 (d, J = 12.1 Hz, 1 H, H14), 6.11 (s, 1 H, H8), 5.95 (d, J = 11.9 Hz, 1 H, H12), 2.13 (s, 3 H, C13-CH3), 1.90-1.80 (m, 1 H, H3), 1.87 (s, 3 H, C13 ′-CH3), 1.85 (s, 3 H, C9-CH3), 1.80-1.70 (m, 1 H, H2 or H4), 1.60-1.50 (m, 3 H, H2 + H3 + H4), 1.40-1.30 (m, 1 H, H2 or H4), 1.32 (s, 3 H, C5-CH3), 1.27 (s, 3 H, C1-CH3), 1.04 (s, 3 H, C1-CH3) ppm. MS (EI+): m/z (%) = 367 (27) [M+ + 1], 366 (100) [M+], 322 (35), 281 (41), 202 (28), 157 (36), 111 (37), 109 (32), 99 (27), 97 (60), 95 (27), 85 (61), 83 (62), 81 (30), 71 (80), 69 (85). HRMS (EI+): m/z calcd for C25H34O2: 366.2559; found: 366.2555. FT-IR (NaCl): ν = 3600-3400 (br, OH), 2960 (s, C-H), 2923 (s, C-H), 2853 (m, C-H), 1930 (w, C=C=C), 1731 (s, C=O), 1662 (s), 1552 (m), 1261 (s) cm-1. UV (MeOH): λmax = 294, 416 nm (Figure [1] ).

Figure 1

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Data for 13g: 1H NMR [600 MHz, (CD3)2CO]: δ = 7.50 (s, 1 H, H10), 7.17 (d, J = 15.6 Hz, 1 H, H7), 7.10 (t, J = 12.8 Hz, 1 H, H15 ′), 6.76 (t, J = 12.3 Hz, 1 H, H15), 6.70-6.60 (m, 2 H, H10 ′ + H14), 6.47 (t, J = 10.4 Hz, 1 H, H11 ′), 6.42 (d, J = 15.6 Hz, 1 H, H8), 6.22 (t, J = 11.5 Hz, 1 H, H14 ′), 6.18 (s, 1 H, H8 ′), 6.00 (s, 1 H, H12), 3.54 (s, 1 H, OH), 2.21 (d, J = 6.0 Hz, 3 H, C13-CH3), 2.00 (m, 1 H, H3 ′), 1.89 (s, 3 H, C9 ′-CH3), 1.90-1.80 (m, 2 H, H4 ′ + H4), 1.60-1.50 (m, 1 H, H2 ′), 1.50-1.30 (m, 7 H, H3 ′ + H2 ′ + H4 ′ + H2 + 2 H3 + H4), 1.36 (s, 3 H, C1 ′-CH3), 1.28 (s, 3 H, C5 ′-CH3), 1.16 (s, 3 H, C1-CH3), 1.13 (s, 3 H, C5-CH3), 1.10-1.00 (m, 1 H, H2), 1.01 (s, 3 H, C1 ′-CH3), 0.91 (s, 3 H, C1-CH3) ppm. 13C NMR [100 MHz, (CD3)2CO]: δ = 204.4 (s, C7 ′), 170.2 (s, C=O), 149.1 (s, C11), 139.8 (d, C14), 138.7 (d, C10), 137.9 (s, C9 ′), 135.7 (s, C13), 135.3 (d, C7), 134.1 (d, C15 ′), 131.5 (d, C15), 130.4 (d, C12 ′), 129.6 (d, C11 ′), 126.5 (s, C9), 124.4 (d, C10 ′), 123.6 (d, C8), 121.3 (s, C6 ′), 120.5 (d, C12), 104.4 (d, C8 ′), 72.7 (s, C6), 71.7 (s, C5 ′), 67.3 (s, C5), 42.6 (t, C4 ′), 42.4 (t, C2 ′), 37.5 (t, C2), 36.2 (s, C1 ′), 35.3 (s, C1), 33.6 (q, C1 ′-CH3), 32.6 (q, C5 ′-CH3), 31.7 (t, C4), 30.2 (q, C1 ′-CH3), 27.4 (q, C1-CH3), 27.1 (q, C1-CH3), 22.0 (q, C5-CH3), 20.0 (t, C3 ′), 18.7 (t, C3), 16.5 (q, C13-CH3), 15.2 (q, C9 ′-CH3) ppm. MS (FAB+): m/z (%) = 558 (10) [M+ + 2], 557 (11) [M+ + 1], 556 (85) [M+], 540 (12), 539 (26), 394 (15), 393 (26), 322 (27), 307 (29), 289 (20), 241 (12), 165 (27). HRMS (FAB+): m/z calcd for C37H49O4: 557.3631; found: 557.3613. FT-IR (NaCl): ν = 3600-3400 (br, OH), 2961 (s, C-H), 2923 (s, C-H), 2849 (m, C-H), 1926 (w, C=C=C), 1749 (s, C=O), 1521 (w), 1449 (w) cm-1 (Figure [2] ).

Figure 2

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Determined by 2D HMQC-TOCSY. Although the geometry of 1,ω-bis(tributylstannyl)-1,3,5,7,9-decapentaene (16) reported by our group was in error (ref.9), the structures of the final carotenoids β,β-carotene and (3R,3′R)-zeaxanthin obtained by Stille coupling of 16 with the corresponding trienyliodides are correct. Isomerization takes place at the carotenoid stage by the action of palladium, since reagent 16 is stable to the Stille coupling reaction conditions.