| 研究実績の概要 |
The purpose of this project is the development of iron-catalyzed C-H activation using mild organometallic reagents such as organoboron compounds. We have previously found that organoborates or trimethylaluminum can be used both as a base and nucleophilic reagent for the activation of carboxylic amides or aromatic carbonyl compounds. However, under these reaction conditions only oxidative coupling with the organometallic reagent was possible. In order to solve this problem, during FY2017 we developed a new aluminum reagent from trimethylaluminum, catechol, and trimethylsilylmethyl chloride. This reagent was used as a base in the presence of an iron/diphosphine catalyst in order to activate an aromatic carbonyl compound. Deuterium labeling showed that the resulting iron intermediate is relatively stable, and it could be trapped by electrophiles such as alkynes, alkyl halides, and diboron reagents.
We have also investigated other reagents, easier to handle and inexpensive, which could be used as a base for organic catalysis. Thus, we found that potassium t-butoxide in the presence of a catalytic amount of an iron salt generates an iron alkoxide ate species capable to activate an aryl chloride and react it with a boron reagent. This reactivity will be exploited in the future for iron alkoxide-catalyzed C-H bond activation.
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