Development of new asymmetric phosphenium salt catalysts, and its application to the construction of chiral tetra-substituted carbon.

磷化合物被称为刘易斯碱性化学品，然而，阳离子膦具有刘易斯酸性特征。我把注意力集中在膦盐上，我发现它们可以作为刘易斯酸性催化剂，用于异-狄尔斯-桤木反应。虽然我合成了多种手性膦盐，但催化不对称反应没有实现。同时，我发现一种手性膦盐的合成中间体双脲化合物与镱形成了良好的配合物，可以催化高反应活性和高立体选择性的Diels-Alder反应。

Phosphorus compounds are known as Lewis basic chemicals, however, cationic phosphines have Lewis acidic character. I focused on phosphenium salts, and I found that they worked as a Lewis acidic catalyst for hetero-Diels-Alder reaction. Although I synthesized a variety of chiral phosphenium salts, catalytic asymmetric reactions were not realized. Meanwhile, I found that one bis-urea compound, which was a synthetic intermediate of chiral phosphenium salt, formed a good complex with Ytterbium to catalyze highly reactive and highly stereoselective Diels-Alder reaction.