Diastereo- and Enantioselective Asymmetric Hydrogenation of α-Amido-β-keto Phosphonates via Dynamic Kinetic Resolution

Tao, Xiaoming; Li, Wanfang; Li, Xiaoming; Xie, Xiaomin; Zhang, Zhaoguo

doi:10.1021/ol303105d

Cited by 42 publications

(13 citation statements)

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“…In 2013, Zhang and co-workers reported a convenient and general protocol for the synthesis of these compounds through Ru-catalyzed hydrogenation of α-amido β-keto phosphonates via DKR (Scheme 13). 29 By using [RuCl(benzene)(S)-SunPhos]Cl as the catalyst, excellent levels of stereoselectivity were observed for the corresponding syn-α-amido β-hydroxy phosphonates (up to 99:1 syn/anti, up to 99.8% ee). The authors demonstrated the crucial role of additives in the stereochemical outcome of the reaction, because a dramatic increase of both dr and ee was observed after the addition of CeCl 3 •7H 2 O.…”

Section: α-Substituted β-Keto Phosphonates and Sulfonesmentioning

confidence: 99%

Recent Developments in Asymmetric Hydrogenation and Transfer Hydrogenation of Ketones and Imines through Dynamic Kinetic Resolution

et al. 2016

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The transition-metal-catalyzed asymmetric transfer hydrogenation (ATH) and asymmetric hydrogenation (AH) of α-and β-substituted ketone or imine derivatives are efficient methods for accessing chiral alcohols or amines bearing up to three stereogenic centers through a dynamic kinetic resolution (DKR) process. This review provides a summary of recent work in this field, focusing on the development of new catalytic systems and on the extension of these asymmetric reductions to new classes of substrates. Conclusion

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Section: α-Substituted β-Keto Phosphonates and Sulfonesmentioning

confidence: 99%

Recent Developments in Asymmetric Hydrogenation and Transfer Hydrogenation of Ketones and Imines through Dynamic Kinetic Resolution

et al. 2016

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“…When α‐methylene was substituted with Me, Et, or Br, high ee values and syn / anti ratios were observed ( 14k – m ). Moreover, in the presence of CeCl 3 •7H 2 O, and under otherwise the same reaction conditions, highly diastereo‐ and enantioselective hydrogenation of α‐amido‐β‐keto phosphonates was realized through dynamic kinetic resolution (DKR; Scheme ) 30…”

Section: β‐Functionalized Ketonesmentioning

confidence: 99%

A Decennary Journey towards the Efficient Asymmetric Hydrogenation of Highly Functionalized Ketones

Lü

Zhang

2016

The Chemical Record

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Around 2006, our group launched a long-term project on the asymmetric hydrogenation of functionalized ketones by using ruthenium complexes with SunPhos ligands. In this review, we recount the burgeoning and blossoming of this project. At the outset, we attempted some benchmark reactions with an array of monofunctionalized ketones, including α- and β-keto esters/amides, β-keto sulfones, phosphonates, and α-hydroxy ketones. For α-keto esters and amides, we discovered that CeCl •7H O was an efficient additive for both activity and enantioselectivity. The element iodine was found to be a valid additive for β-keto sulfones. β,γ-Unsaturated α-keto acids and esters were also hydrogenated to the saturated chiral blocks with good enantioselectivity and a high turnover number. For the α-substituted β-keto esters and phosphonates, exceptionally high stereoselectivity was achieved through dynamic kinetic resolution. Based on these incipient successes, we diverted to bifunctionalized ketone substrates, such as γ-heteroatom-substituted β-keto esters and δ-ketal-β-keto esters. For the δ-ketal-β-keto esters, CaCO was added to stabilize the δ-ketal groups, which ensured the formation of δ-ketal-β-hydroxy esters in good yields and high ee values. More interestingly, γ-halo-γ,δ-unsaturated-β-keto esters were hydrogenated to afford highly enantiopure chiral allyl alcohols under mild and neutral conditions. The distance effect of the directing groups was investigated in β-, γ-, and δ-keto amides; the last two were hydrogenated with the Ru-SunPhos-diamine system. To implement the pinpoint recognition of two carbonyl groups in similar chemical propinquity, we compared the reaction rates of different β-keto acid derivatives. THF was found to be a helpful coordinative solvent to control the chemo- and enantioselectivity for more challenging polycarbonyl substrates, such as 3-oxo glutaric acid derivatives, β,δ-diketo carboxamides, and γ-heteroatom-substituted β-diketones. The effects of solvents and heteroatoms in these substrates were also studied. Applications of these hydrogenation reactions were also exemplified by the employment of the products for important pharmaceutical syntheses.

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“…Cerium chloride heptahydrate (CeCl 3 · 7H 2 O), the most common commercially available source of Ce +3 , finds useful application as a catalyst in heterocyclic synthesis. 31 It is a mild Lewis acid which has low toxicity and is relatively inexpensive. Hence, it is a good candidate for green organic transformations.…”

Section: Introductionmentioning

confidence: 99%

An eco-friendly synthesis of 2-pyrazoline derivatives catalysed by $$\hbox {CeCl}_{3} \cdot 7\hbox {H}_{2}\hbox {O}$$ CeCl 3 · 7 H 2 O

Bhat

Shridhar²,

Ladage

et al. 2017

J Chem Sci

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Diastereo- and Enantioselective Asymmetric Hydrogenation of α-Amido-β-keto Phosphonates via Dynamic Kinetic Resolution

Cited by 42 publications

References 54 publications

Recent Developments in Asymmetric Hydrogenation and Transfer Hydrogenation of Ketones and Imines through Dynamic Kinetic Resolution

Recent Developments in Asymmetric Hydrogenation and Transfer Hydrogenation of Ketones and Imines through Dynamic Kinetic Resolution

A Decennary Journey towards the Efficient Asymmetric Hydrogenation of Highly Functionalized Ketones

An eco-friendly synthesis of 2-pyrazoline derivatives catalysed by $$\hbox {CeCl}_{3} \cdot 7\hbox {H}_{2}\hbox {O}$$ CeCl 3 · 7 H 2 O

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