Abstract:

The esterification of carboxylic acid with alcohol in the presence of catalytic amounts of mineral acids is one of the most methods for preparing esters. The catalysts generally preferred are sulfuric acid or p\|toluenesulfonic acid. But the products esters were racemic when (S)-3-(2′-oxocyclohexyl) propionic acid reacts with alcohols in the presence of sulfuric acid or with p\|toluenesulfonic acid as catalyst. We replace sulfuric acid with Fe₂(SO₄)^₃·xH2O as the catalyst. The optical compound (S)-methy-3-(2′-oxocyclohexyl)propionate, (S)-ethyl-3-(2′-oxocyclohexyl)propionate and (S)-n-butyl-3-(2′-oxocyclohexyl)propionate were obtained. In this paper we also reported that cyclohexanone reacted with methyl acrylate in the presence of potassium thiazolidine-2-thione-4-carboxylate (R)TTCA·K as the chiral catalyst to afford optically active (S)-3-(2′-oxocy-clohexyl) propionate. The mechanism of reaction of cyclohexanone with methyl acrylate in the presence of (R)TTCA·K as the catalyst would be a complex process.

Key words: Fe₂(SO₄)₃·xH₂O; Optically active methyl-3-(2′-oxocyclohexyl)-propionate; Optically active ethyl-3-(2′-oxocyclohexyl)propionate; Optically active n\, butyl-3-(2′-oxocy-clohexyl)propionate; (R)-potassium thiazolidine-2-thione-4-carboxylate