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ActivitiesAssociate Professor Nishikata has succeeded in precise control in adding an alkyl group and a hydrogen atom to an alkyne using a copper catalysis system – The achievement of the free and separate creation of cis and trans configurations of alkenes! - 2017.02.10

 

 

 Image of how a molecule’s three-dimensional structure is controlled by means of a copper catalyst

Alkylated alkenes are important structures for forming pharmaceutical products and agricultural chemicals. An alkylated alkene can have a trans structure, in which the alkyl group and the hydrogen atom in its β position are on the same side, and a cis structure, which is the opposite of the trans structure (the molecules on the left and right in the diagram above), and a variety of synthetic methods have been researched to date. However, it is not easy to control the stereochemistry around these alkenes. In particular, for “hydroalkylation,” which involves adding an alkyl group and hydrogen atom simultaneously to alkynes, which have a carbon-carbon triple bond, it has been difficult to achieve stereoselective addition reactions using conventional methods, despite the fact that alkylated alkenes can be synthesized in the first stage.

This time, Associate Professor (tenure track) Takashi Nishikata and colleagues at the Graduate School of Sciences and Technology for Innovation (Applied Chemistry Field) have succeeded in achieving stereoselective addition of alkyl groups to alkynes by using different hydrogen sources under copper-catalyzed conditions.  They have found that by using silane with alkenes with the cis structure, while on the other hand using alcohol/diboron with those with the cis structure, it is possible to synthesize alkylated alkenes with the respective steric configurations. These research results were published in “ACS Catalysis,” and the number of accesses per month was ranked within the top 20 for the same journal.

As a methodology for selectively synthesizing alkene molecules, future applications are anticipated in the field of complex-molecule precision synthetic chemistry.