Generation of Chirality Triggered by Sunlight Irradiation and Development of New Asymmetric Catalysts

提出了一种从非手性材料出发，无外部手性源进行有效不对称合成的新方法。非手性铬羧酸酯在溶液中的辐照产生了光学活性形式的结晶铬二聚体。阐明了手性的产生机理，并通过考察条件，使产物的光学纯度达到80%。此外，该光学活性产物被用作配体，用于有机金属化合物的催化不对称合成。将该方法扩展到一种新的不对称合成方法，通过2-苯甲酰苯甲酸衍生物与胺的反应，实现了高光学纯度的绝对不对称异吲哚酮的合成。

A new methodology of effective asymmetric synthesis starting from achiral materials without external chiral source was developed. Irradiation of achiral chromonecarboxylic esters in solution afforded crystalline chromone dimers in optically active form. The mechanism of generation of chirality was clarified and the optical purity of the products was attained 80% by examining conditions. Furthermore, the optically active products were utilized as ligands for catalytic asymmetric synthesis using organometallic compounds. Moreover, this methodology was expanded to a new asymmetric synthesis, and the absolute asymmetric synthesis of isoindolinones with high optical purity was achieved by a reaction of 2-benzoylbenzoic acid derivative with amines.