Preface

In a previous book about chirality, entitled Chirality from Molecular Electronic States published in 2019 [1], I wrote in the Preface:

*In chemistry, biology, and physics, "chirality" is an important concept in nature. In chemistry, not only classical stereochemistry but also asymmetric organic synthesis, supramolecular chemistry, construction of bio-related molecules, and molecular recognition have become indispensable structural chemical keywords. However, in view of synthetic chemistry and its structural chemistry, chemistry dealing with chirality in relation to the more fundamental electronic state is still a minority. This book focuses on chiroptical spectroscopy, structural or physical features, and theoretical computation of chirality*.

In contrast to the previous book, this new book about chirality includes contributions from authors in many fields of natural science, providing a wider overview. The book's focus is chirality and organic chemistry, including synthesis and reactions. For

*Mirror Image formula on a piece of "memory bread," which is a famous Japanese cartoon character's item to memorize letters by transferring from the notebook and eating (for examination of mathematics).*

example, the chapter by Ali et al. describes anion-π catalysts in asymmetric synthesis, which is an area of supramolecular chemistry. So far, some important reactions that produce chiral centers have taken place on the π-acidic surface of the anion-π catalyst. This clarifies the importance of anion-π catalysis in the area of asymmetric synthesis.

As I write in the introductory chapter, "Chirality is a concept that is related not only to organic chemistry but also to each field of natural science in a narrow sense, and it is considered that awareness of hierarchy is important for universal and comprehensive understanding." In this way, I would like to continue "fixed-point observations" of chemistry and various sciences, which are three-dimensional mirror images (**Figure 1**), if there is an opportunity to do so in the future..

**Takashiro Akitsu**

**References**

[1] Akitsu T (Ed.), Chirality from Molecular Electronic States, InTech (Rijeka, Croatia) (2019). 978-1-78985- 156-4. (Introductory Chapter: Chirality from Molecular Electronic States. pp1-7)

Department of Chemistry, Faculty of Science, Tokyo University of Science, Tokyo, Japan
