The reaction between hydrazonoyl chlorides and monosubstituted allenes in the presence of catalytic amounts of copper(I) chloride gives 1,3,5-substituted pyrazoles under mild conditions and very short reaction times. This site- and regioselective process involves first the complexation of copper(I) on the external double bond of the allene moiety, followed by nucleophilic attack on the central carbon atom of the so-formed copper(I)-complexed allene by the terminal nitrogen of the hydrazonoyl chloride. Subsequent ring closure to thetarget pyrazole ring is possible in the presence of electron-attracting groups on theallene moiety. A catalytic cycle has been proposed on the basis of the experimental results.


中文翻译：

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当腙酰氯遇到艾伦烯时：一种位点和区域选择性铜（I）催化的方法来制备 5-取代吡唑

在催化量的氯化铜 (I) 存在下，腙酰氯和单取代的丙二烯之间的反应在温和的条件和非常短的反应时间内得到 1,3,5-取代的吡唑。这个位点选择性和区域选择性的过程首先包括铜的络合（I ）的丙二烯部分的外部双键，随后亲核ATTAC ķ （I）上所形成的铜的中心碳原子-complexed丙二烯通过终端腙酰氯的氮。随后环闭合第È目标吡唑环是可能的吸电子基团的在th存在eallene部分。根据实验结果提出了催化循环。