Cyclopropanone derivatives constitute highly strained cycloalkanones with promising applications as three-carbon building blocks in organic synthesis. Due to the presence of a ketone in such a small ring system, all C–C bonds and the carbonyl group are considered to be labile in suitable conditions, leading to a wide variety of synthetic disconnections, including nucleophilic addition, ring expansion, ring-opening, and (formal) cycloaddition. Despite their synthetic potential, the widespread adoption of cyclopropanones as substrates has been considerably hampered by the difficulties associated with the preparation and storage of such unstable compounds, prompting the development of cyclopropanone surrogates that can equilibrate to the parent ketone in situ via elimination. This review summarizes the syntheses and applications of cyclopropanone derivatives and their equivalents, and offers a perspective of the state of the field as well as its expected future directions.1 Introduction2 Preparation of Cyclopropanones and Their Equivalents2.1 Carbenoid Chemistry2.2 Allene Oxide Rearrangement2.3 Ring Closure by Dehydrohalogenation or Dehalogenation2.4 Photolytic Processes2.5 Miscellaneous Formation of Cyclopropanones2.6 Cyclopropanone Equivalents3 Synthetic Applications of Cyclopropanones and Their Equivalents3.1 Nucleophilic Addition to the Carbonyl Group3.2 Ring Expansion3.3 Ring-Opening3.4 Cycloaddition and Formal Cycloaddition4 Conclusion and Outlook

中文翻译：

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环丙酮及其等价物在有机合成中作为三碳结构单元的合成与应用

环丙酮衍生物构成高度紧张的环烷酮，在有机合成中作为三碳结构单元具有广阔的应用前景。由于在如此小的环系中存在酮，所有 C-C 键和羰基在合适的条件下都被认为是不稳定的，导致各种合成断开，包括亲核加成、扩环、环-开环和（正式）环加成。尽管具有合成潜力，但环丙酮作为底物的广泛采用受到与此类不稳定化合物的制备和储存相关的困难的极大阻碍，促使开发可通过消除原位与母体酮平衡的环丙酮替代物。