Ethyl chloroformate → 4-Methyl-4-(tetrahydro-pyran-2-yloxy)-pent-2-ynoic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-(1,1-dimethyl-prop-2-ynyloxy)-tetrahydropyran (10.0 g, 59.4 mmol) in THF (100 mL), cooled to −78° C. was added n-butyl lithium (26 mL, 65 mmol) as a solution in hexanes. The mixture was stirred at −78° C. for 1 h then a solution of ethyl chloroformate (7.0 mL, 108.5 mmol) in THF (100 mL) was added dropwise. The mixture was stirred at −78° C. for 1 h then quenched by addition of a saturated aqueous solution of ammonium chloride. This mixture was diluted with water and extracted with ethyl acetate. The organic phase was dried (sodium sulfate) and concentrated to provide 7.5 g (53%) of 4-methyl-4-(tetrahydro-pyran-2-yloxy)-pent-2-ynoic acid ethyl ester as a clear oil.

Provenance & Evidence