Chapter 7 - Chiral Molecular Tools Powerful for the Preparation of Enantiopure Compounds and Unambiguous Determination of Their Absolute Configurations by X-Ray Crystallography and/or 1H NMR Diamagnetic Anisotropy

Abstract

It is well known that molecular chirality is essential for life processes, and most biologically active compounds are chiral. Hence, in the structural study of biologically active compounds, determination of absolute configuration (AC) becomes the first major issue. The second issue is the synthesis of enantiopure compounds (100% ee). Furthermore, studies on chiral molecular machines, such as the light-powered chiral molecular motor developed by us, have been rapidly progressing in recent years. Thus, the unambiguous AC determination of chiral compounds as well as their chiral syntheses are of vital importance in the field of molecular science and technology. We have recently developed chiral carboxylic acids, CSDP acid, and MαNP acid, which are very powerful for the synthesis of enantiomers with 100% ee and also for the unambiguous AC determination by X-ray crystallography and/or 1H NMR diamagnetic anisotropy. The methods using these chiral molecular tools have been successfully applied to various compounds, and their methodologies and applications are explained throughout this chapter.