Highly Enantioselective Hydrogenation of Amides via Dynamic Kinetic Resolution Under Low Pressure and Room Temperature

Rasu, Loorthuraja; John, Jeremy M.; Stephenson, Elanna B.; Kalapugama, Suneth; Clément, Roxanne; Endean, Riley T.

doi:10.1021/jacs.6b12254

Cited by 39 publications

(24 citation statements)

References 61 publications

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“…In 2017, the group of Bergens achieved the first enantioselective deaminative hydrogenation of α-phenoxy tertiary amides by dynamic kinetic resolution, using a chiral derivative of Noyori-type complex in the presence of (over)stoichiometric amounts of 2-PrONa and 2-PrOH (Fig. 2A13 ) 41 . With the aim of improving catalyst stability and, hence, paving the way for having access to challenging substrates, the same year the groups of Saito 42 and Lv & Zhang 43 published two tetradentate complexes with [Ru-PNNP] structure (Fig.…”

Section: Development Of Homogeneous Catalystsmentioning

confidence: 99%

Homogeneous and heterogeneous catalytic reduction of amides and related compounds using molecular hydrogen

et al. 2020

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Catalytic hydrogenation of amides is of great interest for chemists working in organic synthesis, as the resulting amines are widely featured in natural products, drugs, agrochemicals, dyes, etc. Compared to traditional reduction of amides using (over)stoichiometric reductants, the direct hydrogenation of amides using molecular hydrogen represents a greener approach. Furthermore, amide hydrogenation is a highly versatile transformation, since not only higher amines (obtained by CO cleavage), but also lower amines and alcohols, or amino alcohols (obtained by C-N cleavage) can be selectively accessed by fine tuning of reaction conditions. This review describes the most recent advances in the area of amide hydrogenation using H 2 exclusively and molecularly defined homogeneous as well as nanostructured heterogeneous catalysts, with a special focus on catalyst development and synthetic applications. T he development of green and sustainable methods is a central focus of modern organic synthesis and its applications in various areas of the chemical industry. In this respect, many reduction reactions, traditionally employing stoichiometric amounts of metal hydrides with inherent low atom efficiency 1 , can be favorably replaced by catalytic hydrogenations. In fact, the combination of molecular hydrogen and catalysts does not only allow avoiding formation of waste products 2 , it also opens the door to clean transformations based on renewable energies as the conversion of solar or wind energy to "green" hydrogen is likely to be implemented in the coming years. Among the many reduction reactions known, amide hydrogenation can be encountered as one of the most desired considering the importance of the derived amines in several branches of chemical industry. In fact, since the start of the Green Chemistry Institute Pharmaceutical Roundtable in the United States in 2005, several projects aimed to the achievement of a practical amide hydrogenation methodology have been supported 3,4. The long-term interest of the pharmaceutical industry in this specific transformation is explained by the fact that it ideally affords structurally complex amines, present in many of the currently employed drugs. Furthermore, amines are also in bulk and fine chemicals used in the manufacture of plastics, textiles, surfactants, dyes, and many more 5. Amides play a central role in the chemistry of life, as they are the key elements to generate peptides and proteins from amino acid monomers. At the same time, they are present in artificial

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Section: Development Of Homogeneous Catalystsmentioning

confidence: 99%

Homogeneous and heterogeneous catalytic reduction of amides and related compounds using molecular hydrogen

et al. 2020

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“…Improved enantioselectivity (81 % ee ) was obtained with ( R , R )‐ 1 b as the catalyst (entry 2). Interestingly, addition of alcohols such as i PrOH, CF 3 CH 2 OH (TFE), and (CF 3 ) 2 CHOH (HFIP) to the reaction affects the activities and selectivities of these Mn catalysts (entries 3–5) . Use of a substoichiometric amount of HFIP (10 mol %) as an additive improved the enantioselectivity to 87 %, albeit at a cost of incomplete conversion of 6 a (92 %; entry 5).…”

Section: Figurementioning

confidence: 99%

“…[17] Use of as ubstoichiometric amount of HFIP (10 mol %) as an additive improved the enantioselectivity to 87 %, albeit at ac ost of incomplete conversion of 6a (92 %; entry 5). Under 1mol %loading, (S,S)-1a catalyzed the hydrogenation smoothly at room temperature in methanol under 50 bar of H 2 ,a ffording (S)-7a with 67 % ee with full conversion of 6a (entry 1).…”

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confidence: 99%

Lutidine‐Based Chiral Pincer Manganese Catalysts for Enantioselective Hydrogenation of Ketones

et al. 2019

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Aseries of Mn I complexes containing lutidine-based chiral pincer ligands with modular and tunable structures has been developed. The complex shows unprecedentedly high activities (up to 9800 TON; TON = turnover number), broad substrate scope (81 examples), good functional-group tolerance,a nd excellent enantioselectivities (85-98 %e e) in the hydrogenation of various ketones.T hese aspects are rare in earth-abundant metal catalyzedhydrogenations.T he utility of the protocol have been demonstrated in the asymmetric synthesis of av ariety of key intermediates for chiral drugs. Preliminary mechanistic investigations indicate that an outersphere mode of substrate-catalyst interactions probably dominates the catalysis.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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“…Amide is among the most ubiquitous functional groups [1]. Although the reductive functionalization of amides has been studied extensively, the majority of strategies have focused on the amide reductions via C-O or C-N cleavage, to afford the corresponding amines or alcohols (Scheme 1) [2,3,4,5,6,7,8,9,10,11]. Only a few examples were reported for the amide bond functionalization via the selective activation of the non-carbonyl, C-N σ bond, despite its considerable potential in the synthesis of amide linkage in both chemistry and biology (Scheme 1) [12,13].…”

Section: Introductionmentioning

confidence: 99%

Selective C-N σ Bond Cleavage in Azetidinyl Amides under Transition Metal-Free Conditions

Lai

Adijiang

et al. 2019

Molecules

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Functionalization of amide bond via the cleavage of a non-carbonyl, C-N σ bond remains under-investigated. In this work, a transition-metal-free single-electron transfer reaction has been developed for the C-N σ bond cleavage of N-acylazetidines using the electride derived from sodium dispersions and 15-crown-5. Of note, less strained cyclic amides and acyclic amides are stable under the reaction conditions, which features the excellent chemoselectivity of the reaction. This method is amenable to a range of unhindered and sterically encumbered azetidinyl amides.

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Highly Enantioselective Hydrogenation of Amides via Dynamic Kinetic Resolution Under Low Pressure and Room Temperature

Cited by 39 publications

References 61 publications

Homogeneous and heterogeneous catalytic reduction of amides and related compounds using molecular hydrogen

Homogeneous and heterogeneous catalytic reduction of amides and related compounds using molecular hydrogen

Lutidine‐Based Chiral Pincer Manganese Catalysts for Enantioselective Hydrogenation of Ketones

Selective C-N σ Bond Cleavage in Azetidinyl Amides under Transition Metal-Free Conditions

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