Functionalized hydropentalenes (i.e., bicyclo[3.3.0]octanones) constitute important building blocks for natural products and for ligands for asymmetric catalysis. The assembly and tailored functionalization of this convex roof-shaped scaffold is challenging and has motivated a variety of synthetic approaches including our own contributions, which will be presented in this account. 1 Introduction 2 Biosynthesis of Hydropentalenes 3 Hydropentalenes through the Pauson–Khand Reaction 4 Hydropentalenes through Transannular Oxidative Cyclization of Cycloocta-1,4-diene 5 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Dodecahydrocyclopenta[a]indenes 6 Functionalization of Bicyclo[3.3.0]octan-1,4-diones to Crown Ether Hybrids 7 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Cylindramide 8 Tandem Ring-Opening Metathesis/Ring-Closing Metathesis/Cross-Metathesis of Bicyclo[2.2.1]heptanes 9 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Geodin A 10 Hydropentalenes through Enantioselective Desymmetrization of Weiss Diketones 11 Functionalization of Weiss Diketones by Carbonyl Ene Reactions 12 Functionalization of the Weiss Diketone to Cylindramide and Geodin A Core Units 13 Biological Properties of Bicyclo[3.3.0]octanes 14 Hydropentalenes through Vinylcyclopropane Cyclopentene Rearrangement 15 Functionalization of Bicyclo[3.3.0]octanes toward Chiral Dienes 16 Miscellaneous Syntheses of Hydropentalenes 17 Conclusion and Outlook

中文翻译：

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氢戊烯合成中的冒险与弯路

功能化的氢戊烯（即双环[3.3.0]辛酮）是天然产物和不对称催化配体的重要组成部分。这种凸屋顶形脚手架的组装和定制功能化具有挑战性，并激发了各种合成方法，包括我们自己的贡献，这将在本帐户中介绍。1 引言 2 氢戊烯的生物合成 3 氢戊烯通过 Pauson-Khand 反应 4 氢戊烯通过环辛-1,4-二烯的跨环氧化环化 5 双环 [3.3.0] 辛烷-1,4-二酮官能化为十二氢环戊烷 [a] 烯6 双环[3.3.0]octan-1,4-二酮对冠醚杂化物的官能化 7 双环[3.3.0]octan-1的官能化，