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Synlett 2007(12): 1869-1872  
DOI: 10.1055/s-2007-984498
LETTER
© Georg Thieme Verlag Stuttgart · New York

Selective Aerobic Oxidation of Allylic Alcohols to Carbonyl Compounds Using Catalytic Pd(OAc)2: High Intramolecular Selectivity

Frédéric Batt, Emmanuel Bourcet, Youssef Kassab, Fabienne Fache*
ICBMS, Equipe Cheops, CNRS, UMR 5246 Université Lyon 1, Bât. Raulin, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne, France
Fax: +33(472)448136; e-Mail: fache@univ-lyon1.fr;
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Publikationsverlauf

Received 14 February 2007
Publikationsdatum:
25. Juni 2007 (online)

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Abstract

Allylic alcohols were selectively oxidized into aldehydes or ketones using a Pd(OAc)2-Et3N-O2 system. Diols with one ­allylic function were selectively oxidized, with one of the hydroxyl groups remaining untouched.

Key words

palladium - oxidation - allylic alcohols - selectivity - intramolecular - oxygen

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Typical Procedure: Pd(OAc)2 (0.015 mmol, 3 mol%) and Et3N (0.03 mmol, 6 mol%) were dissolved in THF-toluene (15%; 1.7 mL). Then the substrate (0.5 mmol) was added and the reaction mixture was heated to 45 °C under 1 atm of O2 (balloon) for 20 h. The reaction was monitored by TLC. In the case of total conversion, the product was obtained in its pure form after evaporation of the solvents, precipitation of Pd in Et2O and filtration on celite. In other cases, it was purified by chromatography on silica.

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All the products have been fully characterized by 1H NMR (300 MHz) and 13C NMR (75 MHz) and the analyses are in agreement with published data. Data that were not found in the literature are as follows: Product 5: 1H NMR (300 MHz, CDCl3): δ = 0.83 (s, 9 H), 0.87 (d, J = 6.6 Hz, 3 H), 1.10 (dd, J = 6.4, 14.0 Hz, 1 H), 1.17 (dd, J = 4.0, 14.0 Hz, 1 H), 2.06 (m, 1 H), 2.35 (dd, J = 7.9, 15.5 Hz, 1 H), 2.47 (dd, J = 5.8, 15.5 Hz, 1 H), 5.73 (d, J = 10.3 Hz, 1 H), 6.12 (d, J = 17.5 Hz, 1 H), 6.28 (dd, J = 10.3, 17.5 Hz, 1 H). 13C NMR (75 MHz, CDCl3): δ = 23.1, 26.4, 30.3, 31.4 (Cq), 49.6, 51.2, 128.1, 137.3, 201.0 (Cq). Product 9: 1H NMR (300 MHz, CDCl3): δ = 1.13 (d, J = 7.0 Hz, 3 H), 3.19 (m, 1 H), 3.48 (m, 1 H), 3.70 (m, 1 H), 4.49 (d, J = 3.2 Hz, 2 H), 5.80 (dd, J = 1.1, 10.3 Hz, 1 H), 6.28 (dd, J = 1.1, 17.5 Hz, 1 H), 6.46 (dd, J = 10.6, 17.5 Hz, 1 H), 7.31 (m, 5 H). Product 12: 1H NMR (300 MHz, CDCl3): δ = 2.50 (td, J = 1.0, 5.3 Hz, 2 H), 3.18 (m, 1 H, OH), 3.69 (td, J = 1.0, 5.3 Hz, 1 H), 6.09 (s, 1 H), 6.38 (s, 1 H), 9.53 (s, 1 H). 13C NMR (75 MHz, CDCl3): δ = 31.8, 60.9, 136.6, 147.1 (Cq), 195.3 (Cq). IR (neat): 3394, 2932, 1686, 1437, 1267, 1043, 950, 736 cm-1. Product 13: 1H NMR (300 MHz, CDCl3): δ = 2.33 (s, 3 H), 2.49 (t, J = 6.1 Hz, 2 H), 3.65 (t, J = 6.1 Hz, 2 H), 5.89 (s, 1 H), 6.08 (s, 1 H). 13C NMR (75 MHz, CDCl3): δ = 26.0, 34.7, 62.0, 128.0, 146.4, 200.9 (Cq). IR (neat): 3399, 2932, 1675, 1627, 1369, 1184, 1128, 1050, 948, 735 cm-1. Product 14: 1H NMR (300 MHz, CDCl3): δ = 1.08 (d, J = 7.2 Hz, 3 H), 3.01 (m, 2 H), 3.62 (dd, J = 4.5, 11.1 Hz, 1 H), 3.72 (dd, J = 7.2, 11.1 Hz, 1 H), 5.78 (dd, J = 1.3, 10.1 Hz, 1 H), 6.24 (dd, J = 1.3, 17.5 Hz, 1 H), 6.39 (dd, J = 10.1, 17.5 Hz, 1 H). 13C NMR (75 MHz, CDCl3): δ = 13.8, 45.6, 64.4, 129.3, 135.4, 204.3 (Cq). IR (neat): 3402, 2973, 2880, 1677, 1611, 1458, 1405, 1238, 1193, 1025, 977, 735 cm-1. Product 15: 1H NMR (300 MHz, CDCl3): δ = 1.31 (m, 6 H), 1.57 (m, 4 H), 1.80 (m, 1 H), 2.55 (t, J = 7.3 Hz, 2 H), 3.60 (t, J = 6.6 Hz, 2 H), 5.79 (dd, J = 1.3, 10.3 Hz, 1 H), 6.18 (dd, J = 1.3, 17.5 Hz, 1 H), 6.35 (dd, J = 10.3, 17.5 Hz, 1 H). 13C NMR (75 MHz, CDCl3): δ = 24.2, 25.8, 29.5, 33.0, 39.9, 63.2, 128.3, 136.9, 201.5 (Cq). IR (neat): 3391, 2930, 2857, 1681, 1615, 1463, 1403, 1268, 1075, 736 cm-1.