Influence of Pillararene-Based Host–Guest Chemistry on the Enantioselective Synthesis of 2,3-Dihydroquinazolinones

To clarify the relationship between the host-guest complexation and enantioselectivity of an asymmetric reaction, we studied the impacts of pillar[5]arene-based host–guest chemistry on the asymmetric catalytic synthesis of cyclic dihydroquinazolinones from aldehydes, where the aldehydes meanwhile acted as guests. The addition of different pillar[5]arenes cannot only adjust the reactivity of the substrates but also change the enantiomeric excess of the products. The magnitude of such impacts is influenced by several factors, including the solvent, the temperature, the catalyst, the usage and kind of pillararenes, and the structure of aldehydes. When the pillararene-substrate interactions are strong in the reaction systems, the ee variations of products are mainly decided by the guests, aldehydes, whereas the reaction activities are mainly affected by the hosts, pillar[5]arenes.