- Catalytic Reductions Without External Hydrogen Gas: Broad Scope Hydrogenations with Tetrahydroxydiboron and a Tertiary Amine
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Facile reduction of aryl halides with a combination of 5% Pd/C, B2(OH)4, and 4-methylmorpholine is reported. Aryl bromides, iodides, and chlorides were efficiently reduced. Aryl dihalides containing two different halogen atoms underwent selective reduction: I over Br and Cl, and Br over Cl. Beyond these, aryl triflates were efficiently reduced. This combination was broadly general, effectuating reductions of benzylic halides and ethers, alkenes, alkynes, aldehydes, and azides, as well as for N-Cbz deprotection. A cyano group was unaffected, but a nitro group and a ketone underwent reduction to a low extent. When B2(OD)4 was used for aryl halide reduction, a significant amount of deuteriation occurred. However, H atom incorporation competed and increased in slower reactions. 4-Methylmorpholine was identified as a possible source of H atoms in this, but a combination of only 4-methylmorpholine and Pd/C did not result in reduction. Hydrogen gas has been observed to form with this reagent combination. Experiments aimed at understanding the chemistry led to the proposal of a plausible mechanism and to the identification of N,N-bis(methyl-d3)pyridin-4-amine (DMAP-d6) and B2(OD)4 as an effective combination for full aromatic deuteriation. (Figure presented.).
- Korvinson, Kirill A.,Akula, Hari K.,Malinchak, Casina T.,Sebastian, Dellamol,Wei, Wei,Khandaker, Tashrique A.,Andrzejewska, Magdalena R.,Zajc, Barbara,Lakshman, Mahesh K.
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supporting information
p. 166 - 176
(2020/01/02)
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- Sedimentary Evidence for a Diaromatic Carotenoid with an Unprecedented Aromatic Substitution Pattern
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A novel diaryl isoprenoid (C40H66), possessing a 3,4,5-/2,3,6-trimethyl aromatic substitution pattern, which is attributed to a presently unknown strain of photosynthetic green sulfur bacteria, has been identified in a carbonaceous sedimentary rock.
- Hartgers, Walter A.,Damste, Jaap S. Sinninghe,Koopmans, Martin P.,Leeuw, Jan W. de
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p. 1715 - 1716
(2007/10/02)
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- SELECTIVE REDUCTION WITH LITHIUM ALUMIMIUM HYDRIDE/DIPHOSPHORUS TETRAIODIDE. A MILD CONVERSION OF AROMATIC KETONES TO PARENT HYDROCARBONS
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Treatment of aromatic ketones with the title reagent in boiling benzene gives parent hydrocarbons in good to moderate yields.
- Suzuki, Hitomi,Masuda, Reiko,Kubota, Hirohisa,Osuka, Atsuhiro
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p. 909 - 910
(2007/10/02)
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