Allyl iodide → tetrahydro-4-(2-propen-1-yl)-2H-Pyran-4-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To this was added tetrahydro-pyran-4-carboxylic acid methyl ester (7.2 g, 50 mmol) in THF (10 mL). There was almost no color change (light a little bit). This was stirred at −78° C. for 45 min. Then, a mixture of 5 g of HMPA and 10.92 g of allyl iodide was added via canula. Towards 90% of addition, white precipitate formed suddenly. This mixture was stirred at −78° C. for 20 min, then, the dry ice bath was removed and the stirring was continued to allow the reaction mixture to warm to r.t. over 30 min. When the precipitate was dissolved, the reaction mixture was poured into ice-water (100 mL) and ether (50 mL). The two layers were separated; the aqueous layer was extracted with ether (3×50 mL). The combined organic layers were washed with brine, dried (K2CO3), filtered, and concentrated in vacuo to get 8.75 g (95% yield) of the title compound as a yellow liquid.

Provenance & Evidence