3,3-DIMETHYL-1-BUTENE-1,4-DICARBOXYLATE COMPOUNDS AND 1,3,3-TRIMETHYL-1-BUTENE-1,4-DICARBOXYLATE COMPOUNDS, AND PROCESSES FOR PREPARING 5,5-DIMETHYL-2-OXO-3-CYCLOPENTENE-1-CARBOXYLATE COMPOUNDS AND 3,5,5-TRIMETHYL-2-OXO-3-CYCLOPENTENE-1-CARBOXYLATE COMPOUNDS USING THE SAME

To provide processes for preparing, e.g., 5,5-dimethyl-2-oxo-3-cyclopentene-1-carboxylate compounds and 3,5,5-trimethyl-2-oxo-3-cyclopentene-1-carboxylate compounds, which enable reaction without low temperature reaction equipment, are clean, and achieve a good yield.SOLUTION: A process for preparing a compound represented by the general formula (2) comprises reacting a compound represented by the general formula (1) with a base to cause a Dieckmann condensation. In the formulas, R1 and R2 are each independently a C1-10 monovalent hydrocarbon group; R3 represents H or a methyl group; and the wavy line represents an E-configuration, a Z-configuration, or a mixture thereof.SELECTED DRAWING: None 【課題】低温反応設備を用いずに反応を実施でき、クリーンな方法で且つ収率のよい５，５－ジメチル－２－オキソ－３－シクロペンテン－１－カルボキシレート化合物及び３，５，５－トリメチル－２－オキソ－３－シクロペンテン－１－カルボキシレート化合物等の製造方法の提供。【解決手段】一般式（１）で表される化合物と塩基とを反応させてディークマン縮合することにより、一般式（２）で表される化合物を得る製造方法。JPEG2022021915000031.jpg38170（Ｒ１及びＲ２は夫々独立して、炭素数１～１０の１価の炭化水素基；Ｒ３はＨ又はメチル基；波線は、Ｅ体、Ｚ体又はそれらの混合を表す。）【選択図】なし