4254-29-9Relevant articles and documents
A Mass Spectral Investigation of Water and Acetic Acid Elimination From 1- and 2-Indan Derivatives
Groenewold, G. S.,Gross, M. L.,Zey, R.
, p. 416 - 423 (1982)
Water and acetic acid eliminations from 1- and 2-indan derivatives have been investigated.Deuterium labeling, high resolution peak matching and the metastable peak analysis capabilities of a high resolution triple analyzer (E B E) mass spectrometer were employed to examine the eliminations.These experiments showed that water was lost from 1-indanol via 1,2 and 1,3 processes.These results contrast with those obtained for 1-tetralol, which specifically eliminates water in a 1,4 process involving the benzylic hydrogens.Water elimination from 2-indanol is preceded by a slow hydroxyl-benzylic hydrogen exchange and proceeds specifically 1,2.Water losses from both 1- and 2-indanol are characterized by large kinetic energy releases.Acetic acid elimination is shown to occur specifically 1,3 from 1-acetoxyindan and 1,2 from 2-acetoxyindan.
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Mizuno,K. et al.
, p. 1027 - 1030 (1977)
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Erbium-Catalyzed Regioselective Isomerization-Cobalt-Catalyzed Transfer Hydrogenation Sequence for the Synthesis of Anti-Markovnikov Alcohols from Epoxides under Mild Conditions
Liu, Xin,Longwitz, Lars,Spiegelberg, Brian,T?njes, Jan,Beweries, Torsten,Werner, Thomas
, p. 13659 - 13667 (2020/11/30)
Herein, we report an efficient isomerization-transfer hydrogenation reaction sequence based on a cobalt pincer catalyst (1 mol %), which allows the synthesis of a series of anti-Markovnikov alcohols from terminal and internal epoxides under mild reaction conditions (≤55 °C, 8 h) at low catalyst loading. The reaction proceeds by Lewis acid (3 mol % Er(OTf)3)-catalyzed epoxide isomerization and subsequent cobalt-catalyzed transfer hydrogenation using ammonia borane as the hydrogen source. The general applicability of this methodology is highlighted by the synthesis of 43 alcohols from epoxides. A variety of terminal (23 examples) and 1,2-disubstituted internal epoxides (14 examples) bearing different functional groups are converted to the desired anti-Markovnikov alcohols in excellent selectivity and yields of up to 98%. For selected examples, it is shown that the reaction can be performed on a preparative scale up to 50 mmol. Notably, the isomerization step proceeds via the most stable carbocation. Thus, the regiochemistry is controlled by stereoelectronic effects. As a result, in some cases, rearrangement of the carbon framework is observed when tri-and tetra-substituted epoxides (6 examples) are converted. A variety of functional groups are tolerated under the reaction conditions even though aldehydes and ketones are also reduced to the respective alcohols under the reaction conditions. Mechanistic studies and control experiments were used to investigate the role of the Lewis acid in the reaction. Besides acting as the catalyst for the epoxide isomerization, the Lewis acid was found to facilitate the dehydrogenation of the hydrogen donor, which enhances the rate of the transfer hydrogenation step. These experiments additionally indicate the direct transfer of hydrogen from the amine borane in the reduction step.
A General Method for Photocatalytic Decarboxylative Hydroxylation of Carboxylic Acids
Khan, Shah Nawaz,Zaman, Muhammad Kashif,Li, Ruining,Sun, Zhankui
, p. 5019 - 5026 (2020/05/01)
A general and practical method for decarboxylative hydroxylation of carboxylic acids was developed through visible light-induced photocatalysis using molecular oxygen as the green oxidant. The addition of NaBH4 to in situ reduce the unstable peroxyl radical intermediate much broadened the substrate scope. Different sp3 carbon-bearing carboxylic acids were successfully employed as substrates, including phenylacetic acid-type substrates, as well as aliphatic carboxylic acids. This transformation worked smoothly on primary, secondary, and tertiary carboxylic acids.
Photoinduced electron transfer-promoted reactions using exciplex-type organic photoredox catalyst directly linking donor and acceptor arenes
Yamawaki, Mugen,Asano, Akiko,Furutani, Toshiki,Izumi, Yuki,Tanaka, Yosuke,Osaka, Kazuyuki,Morita, Toshio,Yoshimi, Yasuharu
, (2019/12/26)
Directly linked donor and acceptor arenes, such as phenanthrene/naphthalene/biphenyl and 1,3-dicyanobenzene were found to work as photoredox catalysts in the photoreactions of indene, 2,3-dimethyl-2-butene, and 4-methoxyphenylacetic acid. The new stable organic photocatalyst forms an intramolecular exciplex (excited complex) when irradiated in a polar solvent and shows redox catalyst activity, even at low concentrations. To the best of our knowledge, this is the first example of an intramolecular exciplex working as a redox catalyst.
