Water → Spiro[5.5]undec-1-ene-2-carboxylic acid methyl ester

Participants

Reaction Steps

To a solution of trans-1-hydroxy-spiro[5.5]undecane-2-carboxylic acid methyl ester (2.74 g) obtained in Step 3 in chloroform (20 mL) was added triethylamine (2.02 mL). To the reaction mixture was added dropwise a solution of methanesulfonyl chloride (1.03 mL) in chloroform (5 mL) under ice-cooling, followed by stirring the reaction mixture at room temperature overnight. Then, after addition of water, the reaction mixture was washed therewith. The separated organic layer was dried and concentrated. To the residue were added tetrahydrofuran (30 mL) and 1,8-diazabicyclo[5.4.0]undec-7-ene (3.62 mL), followed by heating the reaction mixture at 60° C. for 3 hours. After cooling down to room temperature, the reaction mixture was poured into water, followed by extraction with ethyl acetate. The organic layer was washed successively with 1N aqueous hydrochloric acid solution and saturated brine, dried and concentrated. The residue was purified by column chromatography on silica gel (ethyl acetate:hexane (volume ratio)=1:8) to give spiro[5.5]undec-1-ene-2-carboxylic acid methyl ester (2.075 g).

Provenance & Evidence