An efficient and practical protocol for the preparation of trifluoromethylpyrrolopyrazole derivatives were developed from the [3 + 2] cycloaddition reaction of readily available trifluoromethyl building blocks such as trifluoromethyl N-acylhydrazones or trifluoroacetohydrazonoyl bromides with maleimides. The methods give 3-trifluoromethylated pyrrolidino [3,4-c]pyrazolidin-4,6-dione and 3-trifluoromethylated dihydropyrrolo [3,4-c]pyrazole-4,6(1H,5H)-diones in good to excellent yields under mild reaction conditions. The 3-trifluoromethylated dihydropyrrolo [3,4-c]pyrazole-4,6(1H,5H)-diones can be smoothly oxidized to 3-trifluoromethylated pyrrolo [3,4-c]pyrazole-4,6(1H,5H)-diones by TCCA under mild reaction conditions.

从现成的三氟甲基结构单元（如三氟甲基 N-酰基腙或三氟乙酰肼基溴化物与马来酰亚胺）的 [3 + 2] 环加成反应，开发了一种高效实用的三氟甲基吡咯并吡唑衍生物制备方案。该方法得到 3-三氟甲基化吡咯烷并 [3,4- c ]pyrazolidin-4,6-dione 和 3-三氟甲基化二氢吡咯并 [3,4-c]pyrazole-4,6(1 H ,5 H )-diones在温和的反应条件下获得优异的产率。3-三氟甲基化二氢吡咯并[3,4- c ]吡唑-4,6(1 H ,5 H )-二酮可以顺利氧化为3-三氟甲基化吡咯并[3,4-c]pyrazole-4,6(1H,5H)-diones by TCCA under mild reaction conditions.