Ethyl chloroformate → (6-Methyl-pyridin-2-yl)-propynoic acid ethyl ester

Reaction equation

[C:1]([C:3]1[CH:8]=[CH:7][CH:6]=[C:5]([CH3:9])[N:4]=1)#[CH:2].[Li+].CCC[CH2-].Cl[C:16]([O:18][CH2:19][CH3:20])=[O:17]>O1CCCC1>[CH2:19]([O:18][C:16](=[O:17])[C:2]#[C:1][C:3]1[CH:8]=[CH:7][CH:6]=[C:5]([CH3:9])[N:4]=1)[CH3:20]

Participants

Procedure

A solution of 2-ethynyl-6-methyl-pyridine (0.5 g, 4.3 mmol) in tetrahydrofuran (20 mL) is cooled to −78° C. and treated with 1.6 M N-butyllithium in hexanes (2.9 mL, 4.7 mmol) and stirred for 0.5 h. This solution is then treated with ethyl chloroformate (2.85 mL, 30 mmol) and stirred for 3 h while the solution warms to room temperature. The reaction is quenched with saturated ammonium chloride solution and extracted with ethyl acetate. The solvent is removed to yield 0.67 g (83%) of desired product as a light yellow oil.