17012-35-0Relevant articles and documents
Organocatalyzed Birch Reduction Driven by Visible Light
Cole, Justin P.,Chen, Dian-Feng,Kudisch, Max,Pearson, Ryan M.,Lim, Chern-Hooi,Miyake, Garret M.
supporting information, p. 13573 - 13581 (2020/09/03)
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 (Ered -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.
The Thermal ortho-Substitution of Phenols by Vinyl Ethers
Pinhey, John T.,Xuan, Phan Thanh
, p. 69 - 80 (2007/10/02)
Pyrolysis of a mixture of phenol and 3,4-dihydro-2H-pyran (6) at 150-180 deg C resulted in the formation of 2-(tetrahydro-2H-pyran-2-yl)phenol (3a) in moderate yield.This selective ortho-substitution reaction has been investigated for a range of phenols and a number of vinyl ethers.While it was found to be a fairly general reaction for phenols, only with the vinyl ether (6) and 2,3-dihydrofuran (28a) was the reaction found to be regioselective.Aluminium phenylate strongly catalyses the reaction of phenol with (6), which proceeded under these conditions at room temperature.An ene-type mechanism is proposed for the reaction.
