Hydrochloric Acid → 1-Cyclopentyl-pent-4-yn-1-one

Participants

Reaction Conditions

Reaction Steps

To a solution of pent-4-ynethioic acid S-pyridin-2-yl ester (17.9 g, 94 mmol), dissolved in THF (900 mL) cooled to −78° C. was added cyclopentylmagnesium bromide (2.0 M, 94 mL, 188.5 mmol). The reaction was stirred for 15 minutes, and then warmed to −50° C. The reaction was poured into 500 mL 1 N HCl and the layers were separated. The aqueous layer was extracted with 2×200 mL diethyl ether and the organic layers were combined. The organics were then washed with 300 mL of 1 N NaOH. The organic layer was dried over Mg SO4, and the solids were removed by filtration. The solvent was removed by rotary evaporation to give the desired compound (14.0 g, 99% yield). 1H NMR (CDCl3) δ: 1.54-1.87 (m, 8H), 1.94 (t, J=2.65 Hz, 1H), 2.45 (dt, J1=7.33 Hz, J2=2.78 Hz, 2H), 2.71 (t, J=7.58 Hz, 2H), 2.87 (p, J=7.96 Hz, 1H).

Provenance & Evidence