ethyl 4-methylpent-2-ynoate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: A solution of 2-azido-1,3-dichloro-benzene (1.0 g) and 4-methyl-pent-2-ynoic acid ethyl ester (1.8 g) in toluene (5 mL) is heated to 120° C. overnight. Two regioisomers are observed in a range of 1:1 to 3:1 in favor of the desired product. The reaction is concentrated under reduced pressure and the residue is purified by flash chromatography, eluting with 5% ethyl acetate in hexanes. 1H NMR (400 MHz, CDCl3) δ 7.48 (d, 2H), 7.42 (t, 1H), 4.22 (q, 2H), 3.64 (m, 1H), 1.46 (d, 6H), 1.15 (t, 3H).

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

Procedure: Under an Ar atmosphere, to a mixture of 3-Methylbutyne (1.5 g, 22.0 mmol) in THF (15 ml) was added a solution of 2.5 M n-BuLi in hexanes (9.68 ml, 24.2 mmol) at −78° C. over 15 min, then the mixture was stirred at −78° C. for 5 min, and at −5˜−10° C. for 30 min. Ethyl chloroformate (2.63 g, 24.2 mmol) was added drop wise at −78° C., then the mixture was stirred at 0° C. for 1 h. The reaction was quenched with saturated aqueous NH4Cl under ice cooling, and the whole was extracted with Et2O. The organic layer was washed with brine, dried over Na2SO4, and then concentrated. Purification by kugelrohr distillation (1˜3 mmHg 70˜80° C.) gave 2b (59%). 2b: colorless oil; 1H-NMR (CDCl3) δ 1.24 (6H, d, J=7.0 Hz), 1.31 (3H, t, J=7.2 Hz), 2.70 (1H, sep, J=7.0 Hz), 4.22 (2H, q, J=7.2 Hz). at −5˜−10° C. for 30 min the mixture was stirred at 0° C. for 1 h The reaction was quenched with saturated aqueous NH4Cl under ice cooling the whole was extracted with Et2O The organic layer was washed with brine dried over Na2SO4 concentrated Purification by kugelrohr distillation (1˜3 mmHg 70˜80° C.)

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

Procedure: A solution of 2-azido-1,3-dichloro-benzene (1.0 g) and 4-methyl-pent-2-ynoic acid ethyl ester (1.8 g) in toluene (5 mL) is heated to 120° C. overnight. Two regioisomers are observed in a range of 1:1 to 3:1 in favor of the desired product. The reaction is concentrated under reduced pressure and the residue is purified by flash chromatography, eluting with 5% ethyl acetate in hexanes. 1H NMR (400 MHz, CDCl3) δ 7.48 (d, 2H), 7.42 (t, 1H), 4.22 (q, 2H), 3.64 (m, 1H), 1.46 (d, 6H), 1.15 (t, 3H).

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

Procedure: A solution of 2-azido-1,3-dichloro-benzene (1.0 g) and 4-methyl-pent-2-ynoic acid ethyl ester (1.8 g) in toluene (5 mL) is heated to 120° C. overnight. Two regioisomers are observed in a range of 1:1 to 3:1 in favor of the desired product. The reaction is concentrated under reduced pressure and the residue is purified by flash chromatography, eluting with 5% ethyl acetate in hexanes. 1H NMR (400 MHz, CDCl3) δ 7.48 (d, 2H), 7.42 (t, 1H), 4.22 (q, 2H), 3.64 (m, 1H), 1.46 (d, 6H), 1.15 (t, 3H).

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: A solution of 2-azido-1,3-dichloro-benzene (1.0 g) and 4-methyl-pent-2-ynoic acid ethyl ester (1.8 g) in toluene (5 mL) is heated to 120° C. overnight. Two regioisomers are observed in a range of 1:1 to 3:1 in favor of the desired product. The reaction is concentrated under reduced pressure and the residue is purified by flash chromatography, eluting with 5% ethyl acetate in hexanes. 1H NMR (400 MHz, CDCl3) δ 7.48 (d, 2H), 7.42 (t, 1H), 4.22 (q, 2H), 3.64 (m, 1H), 1.46 (d, 6H), 1.15 (t, 3H).

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

Procedure: To a solution of 3-methylbut-1-yne (6.32 g), cooled in a dry-ice/acetone bath, in tetrahydrofuran (200 mL) is added 1.6 M N-butyl lithium solution (63.8 mL). After 1 h, ethyl chloroformate (9.33 mL) is added and the reaction mixture is stirred for an additional 1.5 h. The reaction mixture is allowed to warm to room temperature and is quenched with saturated ammonium chloride solution. The reaction is extracted two times with ethyl acetate. The organic layers are combined, washed with brine, dried over sodium sulfate, filtered, and concentrated under reduced pressure to give the title compound (11.5 g). 1H NMR (400 MHz, CDCl3) δ 3.75 (s, 3H), 2.8-2.65 (m, 1H), 1.25-1.23 (d, 6H). is quenched with saturated ammonium chloride solution The reaction is extracted two times with ethyl acetate washed with brine dried over sodium sulfate filtered concentrated under reduced pressure

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

Procedure: Under an Ar atmosphere, to a mixture of 3-Methylbutyne (1.5 g, 22.0 mmol) in THF (15 ml) was added a solution of 2.5 M n-BuLi in hexanes (9.68 ml, 24.2 mmol) at −78° C. over 15 min, then the mixture was stirred at −78° C. for 5 min, and at −5˜−10° C. for 30 min. Ethyl chloroformate (2.63 g, 24.2 mmol) was added drop wise at −78° C., then the mixture was stirred at 0° C. for 1 h. The reaction was quenched with saturated aqueous NH4Cl under ice cooling, and the whole was extracted with Et2O. The organic layer was washed with brine, dried over Na2SO4, and then concentrated. Purification by kugelrohr distillation (1˜3 mmHg 70˜80° C.) gave 2b (59%). 2b: colorless oil; 1H-NMR (CDCl3) δ 1.24 (6H, d, J=7.0 Hz), 1.31 (3H, t, J=7.2 Hz), 2.70 (1H, sep, J=7.0 Hz), 4.22 (2H, q, J=7.2 Hz). at −5˜−10° C. for 30 min the mixture was stirred at 0° C. for 1 h The reaction was quenched with saturated aqueous NH4Cl under ice cooling the whole was extracted with Et2O The organic layer was washed with brine dried over Na2SO4 concentrated Purification by kugelrohr distillation (1˜3 mmHg 70˜80° C.)

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

Procedure: A solution of 2-azido-1,3-dichloro-benzene (1.0 g) and 4-methyl-pent-2-ynoic acid ethyl ester (1.8 g) in toluene (5 mL) is heated to 120° C. overnight. Two regioisomers are observed in a range of 1:1 to 3:1 in favor of the desired product. The reaction is concentrated under reduced pressure and the residue is purified by flash chromatography, eluting with 5% ethyl acetate in hexanes. 1H NMR (400 MHz, CDCl3) δ 7.48 (d, 2H), 7.42 (t, 1H), 4.22 (q, 2H), 3.64 (m, 1H), 1.46 (d, 6H), 1.15 (t, 3H).