Shape- and Size-Tunable Synthesis of Covalent Organic Cages through Rh-Catalyzed Regioselective [2+2+2] Cycloaddition |
| |
| Authors: | Yu Sato Masato Abekura Tomohiro Oriki Dr Yuki Nagashima Prof Dr Hidehiro Uekusa Prof Dr Ken Tanaka |
| |
| Institution: | 1. Department of Chemical Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550 Japan;2. Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550 Japan |
| |
| Abstract: | Covalent organic cages have potential applications in molecular inclusion/recognition and porous organic crystals. Bridging arene units with sp3 atoms enables facile construction of rigid isolated internal vacancies, and various prismatic arene cages have been synthesized by kinetically controlled covalent bond formation. However, the synthesis of a tetrahedral one, which requires twice as much bond formation as prismatic ones, has been limited to a thermodynamically controlled dynamic SNAr reaction, and this reversible covalent bond formation made the resulting cage product chemically unstable. Here we report the Rh-catalyzed high-yielding and highly 1,3,5-selective room temperature 2+2+2] cycloaddition of push-pull alkynes and its application to the synthesis of chemically stable aryl ether cages of various shapes and sizes, including prismatic and tetrahedral forms. These aryl ether cages are highly crystalline and intertwine with each other to form regular packing structures. Some aryl ether cages encapsulated isolated water molecules in their hydrophobic cavity by hydrogen bonding with the multiple ester moieties. |
| |
| Keywords: | Alkynes Aryl Ether Cages Covalent Organic Cages [2+2+2] Cycloaddition Rhodium |
|
|
