Aliphatic alkenes can undergo direct functionalization under mild conditions and without the need for transition-metal catalysts or photolysis, report researchers at Kanazawa University, Kanazawa, Japan. The method promises both economic and environmental benefits for synthesizing nitrogen-containing products and other chemicals, they believe.
The approach isn't just an improvement of known synthetic methods, says Tsuyoshi Taniguchi of Kanazawa's School of Pharmaceutical Sciences (Figure 1). "We believe that this is an unprecedented chemical transformation… Our work demonstrated how we can functionalize [an] organic molecule by using [an] approach different from metal-catalyzed methods."
The researchers activated a C-H bond in alkenes using tert-butyl nitrile and molecular oxygen, producing γ-lactols and nitrate ester. More details appear in a recent article in Chemical Communications.
The approach has broader utility, Taniguchi says. "Indeed, we have already succeeded in obtaining other products. Recently, we published a new paper concerning a related reaction… We found that addition of a little water to the reaction mixture changed the products to acyclic functionalized compounds. Furthermore, we developed direct synthesis of 1,4-diols from simple alkenes using a similar concept…. We also would like to expand this concept to carbon-carbon bond formation. For instance, we expect that some carbon function groups instead of a nitro group may be able to be introduced to alkenes."
"The moderate yield of products remains a main problem," he admits. "It is a difficult problem, but we are now continuing efforts to improve the result by screening reagents or conditions."
The researchers are particularly interested in applying the approach to the production of existing or new pharmaceuticals.