Acetic Acid → 7-Oxobicyclo[3.2.0]hept-2-en-2-carboxylic acid, diphenylmethyl ester

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Reaction Steps

To a solution of 50 g of 6,6-dichloro-7-oxobicyclo[3.2.0]hept-2-en-2-carboxylic acid, diphenylmethyl ester, from Example 4, in 75 mL of tetrahydrofuran, was added 500 mL of acetic acid and 100 g of zinc dust. This mixture was stirred mechanically for 6 hr at room temperature and then diluted with 1 L of methylene chloride and filtered. The filtrate was evaporated to a residue which was partitioned between methylene chloride and water. The organic layer was washed with brine, dried over sodium sulfate, and evaporated to give a colorless solid which, when triturated with 150 mL of ether-petroleum ether (1:1), afforded 35.1 g (85.5%) of crystalline 7-oxobicyclo[3.2.0]hept-2-ene-2-carboxylic acid diphenylmethyl ester: IR (Nujol mull): 1625, 1715, 1785 cm-1 ; NMR (220 MHz; CDCl3): δ 2.57 (1H, m), 2.89 (3H, m), 3.27 (1H, m), 4.48 (1H, m), 6.80 (1H, s), 6.86 (1H, m) and 7.1-7.4 (10H, m).

Provenance & Evidence