1-dimethoxyphosphoryl-4-phenylbut-3-yn-2-one

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-Butyl-lithium (13.5 ml. of a 2.29 M solution in hexane) was added dropwise to a stirred solution of dimethyl methylphosphonate (3.84 g.) in anhydrous tetrahydrofuran (25 ml.) at -78° under argon. After 15 minutes, a solution of ethyl phenylpropiolate (2.5 g.) in anhydrous tetrahydrofuran (20 ml.) was added. The reaction mixture was stirred for 2 hours at -78° C., allowed to warm to ambient temperature and stirred for 18 hours, and adjusted to pH 5 by addition of glacial acetic acid. The tetrahydrofuran was evaporated at room temperature under reduced pressure and the residue was partitioned between water and diethyl ether. The diethyl ether layer was separated, washed with water and dried, and the solvent was evaporated. Chromatography of the crude product on silica gel MFC (75 g.)., eluting with diethyl ether/ethyl acetate (9:1), gave unreacted ethyl phenylpropiolate, and subsequent elution with diethyl ether/ethyl acetate (1:1), gave dimethyl 2-oxo-4-phenylbut-3-ynylphosphonate as an oil, RF = 0.28 (ethyl acetate). The n.m.r. spectrum in deuteriochloroform showed the following absorptions (δ values): to warm to ambient temperature stirred for 18 hours The tetrahydrofuran was evaporated at room temperature under reduced pressure the residue was partitioned between water and diethyl ether The diethyl ether layer was separated washed with water dried the solvent was evaporated , eluting with diethyl ether/ethyl acetate (9:1) gave unreacted ethyl phenylpropiolate, and subsequent elution with diethyl ether/ethyl acetate (1:1)

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-Butyl-lithium (13.5 ml. of a 2.29 M solution in hexane) was added dropwise to a stirred solution of dimethyl methylphosphonate (3.84 g.) in anhydrous tetrahydrofuran (25 ml.) at -78° under argon. After 15 minutes, a solution of ethyl phenylpropiolate (2.5 g.) in anhydrous tetrahydrofuran (20 ml.) was added. The reaction mixture was stirred for 2 hours at -78° C., allowed to warm to ambient temperature and stirred for 18 hours, and adjusted to pH 5 by addition of glacial acetic acid. The tetrahydrofuran was evaporated at room temperature under reduced pressure and the residue was partitioned between water and diethyl ether. The diethyl ether layer was separated, washed with water and dried, and the solvent was evaporated. Chromatography of the crude product on silica gel MFC (75 g.)., eluting with diethyl ether/ethyl acetate (9:1), gave unreacted ethyl phenylpropiolate, and subsequent elution with diethyl ether/ethyl acetate (1:1), gave dimethyl 2-oxo-4-phenylbut-3-ynylphosphonate as an oil, RF = 0.28 (ethyl acetate). The n.m.r. spectrum in deuteriochloroform showed the following absorptions (δ values): to warm to ambient temperature stirred for 18 hours The tetrahydrofuran was evaporated at room temperature under reduced pressure the residue was partitioned between water and diethyl ether The diethyl ether layer was separated washed with water dried the solvent was evaporated , eluting with diethyl ether/ethyl acetate (9:1) gave unreacted ethyl phenylpropiolate, and subsequent elution with diethyl ether/ethyl acetate (1:1)