反应详情

A 4.5 g quantity of 5-methoxycarbonyl-4-methoxycarbonylmethyl-5-(2-pentynyl)-2-cyclopentenone (compound (2-a)) is dissolved in a mixture of 50 ml of n-hexhane and 50 ml of acetone, and 7 g of a Lindlar catalyst is added to the solution. Hydrogen gas is introduced into the solution with stirring. The reaction is completed when the solution has absorbed the theoretical amount of the gas. On completion of the reaction, the catalyst is filtered off from the reaction mixture, and the filtrate is concentrated at reduced pressure. The residue is distilled in a vacuum, affording 5-methoxycarbonyl-4-methoxycarbonylmethyl-5-(cis-2-pentenyl)-2-cyclopentenone (compound (2-b), R1 =CH3, R2 =CH3) in a yield of 99.8%, b.p. 81-85° C./0.005 mm Hg.

1. additionis added to the solution
2. customhas absorbed the theoretical amount of the gas
3. customOn completion of the reaction
4. filtrationthe catalyst is filtered off from the reaction mixture
5. concentrationthe filtrate is concentrated at reduced pressure
6. distillationThe residue is distilled in a vacuum