Hydrochloric Acid → (3aS*,6aR*)-5-Methylidene-hexahydro-cyclopenta[c]furan-1-one

Participants

Reaction Steps

At −15° C., a solution of 2-methoxycarbonyl-4-methylidenecyclopentanecarboxylic acid (189.2 g; 1.027 mol) in THF (1 l) was admixed with triethylamine (156.6 ml; 1.130 mol) and ethyl chloroformate (18.2 ml; 1.027 mol), and the reaction mixture was stirred at room temperature for 1 h. The precipitate was filtered off with suction and the filtrate was concentrated, taken up in methanol (1 l), NaBH4 (97.146 g; 2.568 mol) was added a little at a time at −15° C. and the mixture was stirred at room temperature for 1 h. For work-up, the mixture was admixed with 1 N HCl, saturated with NaCl and extracted with ethyl acetate. The combined organic phases were dried (Na2SO4) and concentrated, and the crude product was purified by chromatography.

Provenance & Evidence