Potassium Iodide → (R)-1-(3-(10,11-dihydro-5H-dibenzo[a,d]cyclo-hepten-5-ylidene)-1-propyl)-2-piperidinecarboxylic acid ethyl ester

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Reaction Steps

5-(3-Bromo-1-propylidene)-10,11-dihydro-5H-dibenzo[a,d]cycloheptene (2.7 g, 8.6 mmol, prepared as described in WO 9518793), potassium carbonate (7.14 g, 52 mmol), potassium iodide (1.4 g 8.6 mmol), and (R)-(+)-2-piperidine-carboxylic acid ethyl ester hydrochloride (3.3 g, 17 mmol) were mixed in methyl ethyl ketone (50 ml) and heated at reflux temperature for 3 days. After cooling to room temperature, ethyl acetate (100 ml) was added and the mixture was washed with water (2×100 ml). The organic phase was dried (MgSO4) and evaporated in vacuo. The residue was purified by column chromatography on silica gel (600 ml), using a mixture of ethyl acetate and heptane (1:4) as eluent. This afforded 2.62 9 (78%) of (R)-1-(3-(10,11-dihydro-5H-dibenzo[a,d]cyclo-hepten-5-ylidene)-1-propyl)-2-piperidinecarboxylic acid ethyl ester as an oil.

Provenance & Evidence