Triethylamine → 1,2a,7,7a-Tetrahydro-cyclobuta(a)inden-2-one

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Reaction Steps

To a solution of 2-allyl phenyl acetic acid (Example I2, Step 2, 0.095 g, 0.539 mmol) in dichloromethane (25 mL) was added at 0° C. 1-chloro-N,N,2-trimethyl-1-propenylamine (0.078 mL, 0.593 mmol). The solution was stirred for 1 h and then heated to reflux. Then, a solution of triethylamine (0.082 mL, 0.593 mmol) in dichloromethane (4 mL) was added slowly over two hours to the solution of the acid chloride at reflux. The reaction mixture was stirred for another 2 h and then cooled down. The solvents were removed in vacuo and the residue was purified by flash chromatography eluting with cyclohexane and ethyl acetate (20/1) to give 1,2a,7,7a-tetrahydro-2H-Cyclobut[a]inden-2-one (colourless oil, 56 mg, 66%) The analytical data were identical to the product obtained with the method A.

Provenance & Evidence