Open AccessOrganocatalyzed Birch Reduction Driven by Visible Light
Author(s) -
Justin P. Cole,
Dian-Feng Chen,
Max Kudisch,
Ryan M. Pearson,
ChernHooi Lim,
Garret M. Miyake
Publication year - 2020
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.0c05899
Subject(s) - chemistry , birch reduction , photoredox catalysis , catalysis , photochemistry , benzene , reactivity (psychology) , perylene , visible spectrum , photocatalysis , combinatorial chemistry , organic chemistry , molecule , physics , optoelectronics , medicine , alternative medicine , pathology
The Birch reduction is a powerful synthetic methodology that uses solvated electrons to convert inert arenes to 1,4-cyclohexadienes-valuable intermediates for building molecular complexity. Birch reductions traditionally employ alkali metals dissolved in ammonia to produce a solvated electron for the reduction of unactivated arenes such as benzene ( E red < -3.42 V vs SCE). Photoredox catalysts have been gaining popularity in highly reducing applications, but none have been reported to demonstrate reduction potentials powerful enough to reduce benzene. Here, we introduce benzo[ ghi ]perylene imides as new organic photoredox catalysts for Birch reductions performed at ambient temperature and driven by visible light from commercially available LEDs. Using low catalyst loadings (<1 mol percent), benzene and other functionalized arenes were selectively transformed to 1,4-cyclohexadienes in moderate to good yields in a completely metal-free reaction. Mechanistic studies support that this unprecedented visible-light-induced reactivity is enabled by the ability of the organic photoredox catalyst to harness the energy from two visible-light photons to affect a single, high-energy chemical transformation.