THE CLAISEN AND OTHER [3,3] SIGMATROPIC REARRANGEMENTS, ITS APPLICATION IN ORGANIC CHEMISTRY: A SUBJECT FIELD REVIEW

For more than 100 years since its discover, the Claisen rearrangement has often become an object of research and has been of interest to several generations of organic chemists, which has been reflected in the number of papers on the topic published in the literature. However, 20-30 years ago, only specific issues related to this type of rearrangement have been addressed, the studies on the stereochemical aspects of the reaction deserving special mention. This review provides a general overview covering the most relevant topics related to the Claisen rearrangement, starting from its first publication by Ludwig Claisen in 1912 as a new [3,3] reorganization of allyl aryl (or vinyl) ethers up to its recent applications in different organic chemistry areas. The review includes a brief description of the Claisen rearrangement and other [3,3] rearrangements, the presentation of the most outstanding applications of the reactions. A Prism protocol was used for the review creation. The Scopus database was used to retrieve documents in peer-reviewed journals. VOSviewer was used to display current trends in research areas. At the initial stage of the work, 998 articles were selected, 43 of which were included in the review. After a detailed study of the articles, I identified the following thematic sections: Claisen rearrangement, Eschenmoser rearrangement, Thio-Claisen rearrangement, Retro-Claisen rearrangement, synthesis of heterocyclic compounds, synthesis of carbocyclic acid derivatives, synthesis of dienes, synthesis of carbocyclic skeletons. The diagrams “Prevalence of studies by country” and “Prevalence of articles by journal titles” were also compiled. This review can be of interest to organic chemists, can be used for further research of [3,3] sigmatropic rearrangements, for the synthesis of new compounds that can be used in various fields from construction to medicine.