Date: 10 June 2021 | Category: News
Angewandte Chemie has published the paper entitled “Decatungstate-mediated C(sp3)‒H Heteroarylation via Radical-Polar Crossover in Batch and Flow”[1], in which Prof Tim Noël, in collaboration with Eli Lilly and Vapourtec, describes a direct net-oxidative C(sp3)-H heteroarylation.
This paper reports for the first time the combination of hydrogen atom transfer (HAT) photocatalysis with radical-polar crossover enabling a direct route to generate C(sp3)-N bonds.
Vapourtec’s Dr Manuel Nuño commented: “Our fruitful collaboration with Professor Noël has brought photochemistry to a new level by enabling inert bonds, such C-H, to be easily accessible. In this recent publication, Noël’s team used our High-power LED to combine HAT photocatalysis with radical-polar crossover creating tertiary amines. They demonstrated the robustness of the method by synthesising 40 different compounds, including biologically relevant molecules such as steroids (stanozolol), terpenoids ((‒)-ambroxide) or antimitotics (podophyllotoxin).
This publication shows how an inert bond, such as C-H can be activated under mild conditions, to synthesise molecules of interest with excellent atom efficiency. Professor Noël and his group at Amsterdam are opening new ways of doing clean chemistry, and we are delighted to have contributed to this chemistry with our flow chemistry systems.
Now with one set-up, our customers can explore HAT photochemistry using our range of High-power LEDs, as well as exploring a 4π-electrocyclisation with more energetic wavelengths (<300 nm) [2]. In addition to LED light sources, the Vapourtec UV-150 photochemical reactor provides the option to use either low or medium pressure mercury lamps to access wavelengths in the range 220 nm to 360 nm. These more energetic wavelengths are currently not attainable by LED systems at the radiant power required for meso scale chemistry.
Tim Noël commented “The UV-150 is a flexible photochemical reactor that can be configured for a wide variety of chemistries by changing the UV source. Our work has been focused on the use of decatungsten, an inexpensive photocatalyst, which needs 365 nm for activation. Having the option of using standard LEDs for screening and High-power LED for process optimisation is a read advantage.
References
[1] T. Wan et al., “Decatungstate-mediated C(sp3)‒H Heteroarylation via Radical-Polar Crossover in Batch and Flow,” Angew. Chemie Int. Ed., vol. n/a, no. n/a, May 2021
[2] Vapourtec Ltd, “Application Note 37 – Photochemical Transformation of Methyl Coumalate,” 2015.
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