Sodium Hydroxide → cis-4-Tetrahydropyranyloxy 2-cyclopentenol

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Reaction Steps

A slurry of lithium aluminum hydride (222 mg, 5.8 mnmol), lithium iodide (3.2 g, 24 mmol), tert-butyl methyl ether (6 mL) and toluene (16 mL) is cooled to -15° C. A solution of 4-(tetrahydro-pyran-2-yloxy)-cyclopent-2-enone (2.179 g, 11.97 mnmol, prepared in example 5) in tert-butyl methyl ether (2 mL) and toluene (2 mL) is added dropwise over 40 minutes. The reaction mixture is allowed to stir for 30 minutes. Then sodium hydroxide (1N, 5 mL) is added slowly to the reaction mixture. The slurry is filtered and the resulting phases separated. The aqueous phase is extracted with ethyl acetate (2×10 mL). The organic extracts are combined with the organic phase, dried over magnesium sulfate, filtered and concentrated under vacuum. The crude oil is then purified by chromatography (silica gel, 30 g, 50% ethyl acetate/hexane, 400 mL) to provide the title compound (1.62 g, 73%), cis/trans/l-2+l-4 addition, 88/8/4; 1H NMR (CDCl3) δ 6.1 (m, 1 H), 4.7 (m, 1 H), 4.6 (m, 2 H), 3.9 (m, 1 H), 3.5 (m, 1 H), 2 .7 (m, 1 H), 1.4-2.0 (m, 8 H) 13C NMR (CDCl3) δ 137.2,137.1, 134.8, 133.6, 98.3, 97.8, 79.7, 79.5, 74.7, 74.5, 62.6, 62.5, 42.0, 41.1, 31.1, 30.9, 25.4, 19.6, 19.5; IR (neat) νmax 2944, 2870, 2855, 1723, 1348, 1202, 1182, 1152, 1128, 1078, 1032 cm-1 ; MS (CI) m/e (% relative intensity) 183 (M+H+, 7), 167 (M+H+ --H2O, 40), 85(100).

Provenance & Evidence