College of Science Professor Mao Minoura and Graduate School of Science Ph.D. course student Mariko Yukimoto (now an assistant professor at the Kyoto University Institute for Chemical Research) succeeded in developing a novel primary alkyl steric protection group and synthesizing tetraalkyldisilene. Their results appeared as a Selected Paper in the April 2018 edition of the Bulletin of the Chemical Society of Japan, an international English-language journal published by the Chemical Society of Japan.
In the present study, the development of a novel aliphatic substituent enabled the synthesis and isolation of a stable tetraalkyldisilene, and the structure of tetraalkyldisilene was clarified using single-crystal X-ray structure analysis at the SPring-8 large synchrotron radiation facility. The development of a versatile bulky steric protection group that can be used to synthesize highly reactive chemical species could help elucidate the properties of unknown chemical bonds and be applied in areas such as novel functional materials and materials with catalytic functions.
This study was supported by Rikkyo University Special Fund for Research (Rikkyo University SFR graduate student research); the Ministry of Education, Culture, Sports, Science and Technology’s Program for Strategic Research Foundation at Private Universities; a scientific research grant from the Japan Society for the Promotion of Science; and SPring-8 Budding Researchers Support Program for Ph.D. student. It was chosen as a Selected Paper in the April 2018 edition of the Bulletin of the Chemical Society of Japan, an international English-language journal published by the Chemical Society of Japan.
* Study group
College of Science, professor Mao Minoura
Graduate School of Science, Ph.D. course student (now assistant professor at Kyoto University Institute for Chemical Research) Mariko Yukimoto
Simultaneously, bulky steric protection groups were designed and developed to explore the properties of highly reactive chemical species. However, compared to aromatic substituents, which are rigid and easily undergo functional group transformation, research on aliphatic substituents lagged due to the difficulty of developing protection groups.
2. Methods and results
In addition, a substituent with increased bulkiness was designed by amplifying the aromatic rings of the triptycyl group. Amplification of the triptycyl group’s aromatic rings was achieved in 1 stage at high yield, obtaining a protection group through a simple, textbook reaction.
In addition, these triptycyl frameworks were observed to fit together like gears, with this interlocking effectively protecting the CH2-Si=Si-CH2 portions. Even in solution, disilene 2 was observed as a single component and no isomerization to trans forms was observed.
Moreover, disilene 2 did not break down even when heated to more than 300 ºC, exhibiting a high degree of thermal stability. It oxidized in air, which confirms that the triptycyl-methyl framework provides both steric protection and reaction space.
3. Future prospects
The substituent developed for this study could be used in the kinetic stabilization of unknown chemical species to explore the properties of novel chemical bonds, and could lead to the development and application of chemical species with novel catalytic functions and physical properties.
4. Article information
The Synthesis of a Novel Bulky Primary Alkyl Group and Its Application toward the Kinetic Stabilization of a Tetraalkyldisilene
Mariko Yukimoto, Mao Minoura
Bulletin of the Chemical Society of Japan
Feb 28, 2020