Hydrochloric Acid → Spiro[4.5]dec-6-ene-7-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of the crude 6-methanesulfonyloxy-spiro[4.5]decane-7-carboxylic acid methyl ester (22 g) obtained in Step 4 in tetrahydrofuran (135 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (13.8 mL), followed by stirring the reaction mixture at 60° C. for 1.5 hours. After ice-cooling and adding 1N aqueous hydrochloric acid solution (102 mL), the reaction mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried and concentrated. The residue was purified by column chromatography on silica gel (ethyl acetate:hexane (volume ratio)=3:97 to 25:75) to give spiro[4.5]dec-6-ene-7-carboxylic acid methyl ester (5.485 g).

Provenance & Evidence