Front Cover: Photocatalytic Radical Addition to Levoglucosenone (Eur. J. Org. Chem. 1/2022)

Abstract

The Front Cover shows the stereo and regio selective addition of radical species such as alkyl or formamidyl radicals to levoglucosenone. Levoglucosenone is a biobased platform chemical obtained from celluloses. The radical intermediates are generated by hydrogen atom transfer involving photocatalysis with tetra‐n‐butylammonium decatungstate (TBADT). Cover picture created with the help of Tony Leclet. More information can be found in the Article by N. Hoffmann et al.

Synthesis of New Morphinan Opioids by TBADT‐Catalyzed Photochemical Functionalization at the Carbon Skeleton**

“…This study began with attempts to functionalize enone 1 a with carbon‐centered radicals using tetra‐ n ‐butylammonium decatungstate (TBADT) as the HAT photocatalyst (Figure 2). [7,8] TBADT is one of the most versatile HAT photocatalysts, being able to generate radicals from C−H bonds at benzylic and allylic positions, α‐ to heteroatoms, and formyl groups, as well as at secondary or tertiary C−H bonds of simple alkyl groups [7] . However, we were mindful that this very same versatility could present challenges of functional group incompatibility with a highly functionalized substrate such as 1 a , which contains several different types of C−H bonds that could also potentially react with TBADT (Figure 2).…”

Humins‐Like Solid Support for Palladium Immobilization: Highly Efficient and Recyclable Catalyst for Cross‐Coupling Reactions

“…Cyrene™ is mainly produced by the Circa group, with a productivity of 50 tons/year [73] . Cyrene™ has many applications, some of them including liquid‐liquid extraction, [74] lignin fractionation [75] as well as its use as starting material in organic synthesis [76] . Recently, Cyrene™ has been successfully applied as a solvent for cross‐coupling reactions including Suzuki and Sonogashira couplings [77,78] .…”

“…[73] Cyrene™ has many applications, some of them including liquid-liquid extraction, [74] lignin fractionation [75] as well as its use as starting material in organic synthesis. [76] Recently, Cyrene™ has been successfully applied as a solvent for cross-coupling reactions including Suzuki and Sonogashira couplings. [77,78] Therefore, the scope for Heck reaction using Cyrene™ as the solvent for several aryl halides is shown in Table 4.…”

Tetrabutylammonium decatungstate (TBADT), a compelling and trailblazing catalyst for visible-light-induced organic photocatalysis

“…TBADT was used as a photocatalyst in a stereoselective photocatalytic radical addition to levoglucosenone, as reported by Hoffmann and coworkers, (Scheme 27). 51 A wide range of radicals derived from alkanes, aldehydes, formamide, cyclic ethers, or cyclic acetals were produced and stereoselectively added to levoglucosenone. TBADT acts as a photocatalyst and an efficient hydrogen abstracting agent in the process.…”