Diisobutylaluminum hydride → [5-(3-Oxo-propyl)-tricyclo[8.2.1.03,8]trideca-3(8),4,6-trien-13-yl]-carbamic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

DIBAL-H (1M in toluene, 855 μl, 0.855 mmol) was added dropwise to a stirred solution of the product of Step 1 (290 mg, 0.777 mmol) in toluene (8 ml) maintaining the reaction temperature below −70° C. After stirring at −78° C. for 2 hours, more DIBAL-H (77 μl) was added and stirring was continued for 2 additional hours at −78° C. The mixture was quenched with methanol at −78° C., allowed to warm to room temperature and dispersed between ethyl acetate and 1N HCl. The organic phase was washed with sodium bicarbonate solution (sat), brine, dried and concentrated to give a colourless oil. Analysis by NMR showed ˜15% starting ester present, so the product was subjected to a further treatment with DIBAL-H (122 μl) for 2 hours at −78° C. as described above. The crude product was purified by column chromatography on silica gel eluting with 5:1 isohexane-ethyl acetate to give a colourless oil 149 mg (56%).1 NMR (CDCl3, 360 MHz) δ 9.81 (1H, s), 7.00 (1H, m), 6.90 (2H, m), 4.97 (1H, m), 4.04 (1H, m), 2.86–3.03 (4H, m), 2.75 (2H, m), 2.45–2.63 (4H, m), 1.71 (2H, m), 1.47 (9H, s), 1.19 (2H, m).

Provenance & Evidence