Stabilization of neutral oxophlorin π-radicals by bulky meso-alkyl groups
The 15-tert-butyl-5-oxophlorin 1 forms a stable, neutral π-radical species 2, in high yield; the 13,17-bis-unsubstituted 5-oxophlorin analogue 5, under similar conditions, affords the 15-iso-5-oxophlorin 6 and 15-hydroxy compound 7 (both characterized by X-ray crystallography), the latter demonstrating the trapping of the π-radical by dioxygen.
Publication Source (Journal or Book title)
Khoury, R., Jaquinod, L., Shachter, A., Nelson, N., & Smith, K. (1997). Stabilization of neutral oxophlorin π-radicals by bulky meso-alkyl groups. Chemical Communications (2), 215-216. https://doi.org/10.1039/a607076k