Regioselective deuteration of alcohols in D2O catalysed by homogeneous manganese and iron pincer complexes
We report a convenient and cost-effective protocol for the regioselective deuteration of primary and secondary alcohols using Earth abundant homogeneous first row transition metal pincer catalysts. D2O is utilized as both a deuterium source and a solvent, allowing for a benign inexpensive process. Depending on the metal selected (Mn or Fe), a high degree of deuterium incorporation was observed selectively either at the α and β position (Mn) or exclusively at the α position (Fe), for primary alcohols. This simple, efficient, and cost-effective protocol for alcohol C-H bond deuteration constitutes a powerful tool for the large scale synthesis of deuterated molecules.
Ruthenium-Catalyzed Deuteration of Alcohols with Deuterium Oxide
The catalytic properties of a series of ruthenium complexes for H/D exchange between D2O and alcohols were studied. The catalytic activity of the ruthenium complexes and the regioselectivity of the H/D exchange reactions were found to be dependent on the auxiliary ligands. While ruthenium η6-cymene complexes such as [(η6-cymene)RuCl(NH2CH2CH2NTs)]Cl, (η6-cymene)RuCl2/NH2CH2CH2OH, and (η6-cymene)Ru{(S,S)-NHCHPhCHPhNTs} catalyzed regioselective deuteration of alcohols with D2O at the β-carbon positions only, octahedral ruthenium complexes such as RuCl2(2-NH2CH2Py)(PPh3)2 (2-NH2CH2Py = 2-aminomethylpyridine) and RuCl2(NH2CH2CH2NH2)(PPh3)2 catalyzed regioselective H/D exchange reactions of D2O with alcohols at both the α- and β-carbon positions of alcohols. The H/D exchange reactions proceed through reversible dehydrogenation of alcohols and hydrogenation of carbonyl compounds involving hydride species and H/D exchange among D2O and carbonyl and hydride species. The different regioselectivities of the H/D exchange reactions can be related to the relative ease of H/D exchange of ruthenium hydride intermediates with D2O. (Chemical Equation Presented).
Bai, Wei,Lee, Ka-Ho,Tse, Sunny Kai San,Chan, Ka Wing,Lin, Zhenyang,Jia, Guochen
supporting information
p. 3686 - 3698
(2015/08/24)
SUBSTITUTED 4-AMINO-PIPERIDINES
The present invention relates to new substituted 4-amino-piperidine opioid receptor modulators, pharmaceutical compositions thereof, and methods of use thereof
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Page/Page column 20
(2010/02/17)
Hydrogen Transfer Reactions, 7. Regio- and Stereoselectivity in the Dehydrogenation Steps during Homogeneously Catalysed Hydrogen Transfer
In the disproportionation of 1,2-dihydronaphthalene catalysed by metal complexes, especially by the Wilkinson catalyst (7), the elimination occurs in two steps.The abstraction of the first hydrogen proceeds with but a small preference for the 2-position - in contrast to dehydrogenations via hydride transfer.The second hydrogen is removed highly stereospecifically from the vicinal cis-position, the acceptor being cis-hydrogenated.Intermolecular H/D-scrambling may occur via allyl hydrido complexes.
Gessner, Uwe,Heesing, Albert
p. 2593 - 2606
(2007/10/02)
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