| 摘要 |
<p>The present invention relates to a process for preparing (S)-4-hydroxy-3-methyl-2-(2-propynyl)-cyclopent-2-en-1-one, an important intermediate for the synthesis of insecticides, which comprises condensing cis-(1R, 2S)-3,3-dimethyl-2-(dihydroxymethyl)-cyclopropanecarboxylic-lactone, wherein R2 is a hydrogen atom or a C1-C4 alkyl group, with (RS)-4-hydroxy-3-methyl-2-(2-propynyl)-cyclopent-2-en-1-one in the presence of an acidic catalyst while removing a compound of the formula, R2OH wherein R2 is as defined above, the byproduct from the reaction system, to form cis-(1R, 2S)-3,3-dimethyl-2-[(4S)-3-methyl-2-(2-propynyl)-cyclopent-2-en-1-on-4 -yloxyhydroxymethyl]-cyclopropanecarboxylic lactone as a crystalline form separated from the mixture, and solvolyzing the cis-(1R, 2S)-3,3-dimethyl-2-[(4S)-3-methyl-2-(2-propynyl)-ciclopent-2-en-1-on-4 -yloxyhydroxymethyl]-cyclopropane-carboxylic lactone with a compound of the formula, R1OH wherein R1 is a hydrogen atom or a C1-C4 alkyl group, in an alkaline condition or in the presence of an acidic catalyst.</p> |
