Highly Enantioselective Catalytic System for Asymmetric Copolymerization of Carbon Dioxide and Cyclohexene Oxide

Hua, Yuan‐Zhao; Lu, Liu‐jie; Huang, Pei‐Jin; Wei, Donghui; Tang, Mingsheng; Wang, Min‐Can; Chang, Junbiao

doi:10.1002/chem.201403088

Cited by 52 publications

(27 citation statements)

References 69 publications

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“…The same group also demonstrated the stereoselective alternating copolymerization of cyclohexene oxide and CO 2 with dimeric zinc complexes for the first time 25 . Besides, improved catalysts are still desirable to better control the properties of the resulting materials 26 . Similarly, many efforts are also devoted to designing catalysts able to promote the reaction of CO 2 with less-reactive oxiranes, which could also provide novel materials 27 .…”

Section: Box 1 | Coordination Modes Of Co 2 With Transition Metalsmentioning

confidence: 99%

Using carbon dioxide as a building block in organic synthesis

et al. 2015

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Carbon dioxide exits in the atmosphere and is produced by the combustion of fossil fuels, the fermentation of sugars and the respiration of all living organisms. An active goal in organic synthesis is to take this carbon-trapped in a waste product-and re-use it to build useful chemicals. Recent advances in organometallic chemistry and catalysis provide effective means for the chemical transformation of CO 2 and its incorporation into synthetic organic molecules under mild conditions. Such a use of carbon dioxide as a renewable one-carbon (C1) building block in organic synthesis could contribute to a more sustainable use of resources.A more sensible resource management is the prerequisite for the sustainable development of future generations. However, when dealing with the feedstock of the chemical industry, the level of sustainability is still far from satisfactory. Until now, the vast majority of carbon resources are based on crude oil, natural gas and coal. In addition to biomass, CO 2 offers the possibility to create a renewable carbon economy. Since pre-industrial times, the amount of CO 2 has steadily increased and nowadays CO 2 is a component of greenhouse gases, which are primarily responsible for the rise in atmospheric temperature and probably abnormal changes in the global climate. This increase in CO 2 concentration is largely due to the combustion of fossil fuels, which are required to meet the world's energy demand 1 . Obviously, there is an urgent need to control CO 2 emissions and develop efficient carbon capture systems. Although the extensive use of carbon dioxide for chemical production cannot solve this problem alone, CO 2 is a useful one-carbon (C1) building block in organic synthesis due to its abundance, availability, nontoxicity and recyclability. As a result, valorization of CO 2 is currently receiving considerable and ever increasing attention by the scientific community 2-4 . However, activation and utilization of CO 2 is still problematic due to the fact that it is the most oxidized form of carbon, which is also thermodynamically stable and/or kinetically inert in certain desired transformations. Consequently, most of the known studies used highly reactive substrates and/or severe reaction conditions to activate CO 2 , limiting the application of such methods. In particular, the catalytic coupling of CO 2 with energy-rich substrates, such as epoxides and aziridines, to generate polycarbonates/polycarbamates and/or cyclic carbonates/carbamates has drawn significant attention over the past decades. To create C-C bonds with CO 2 , the use of carbon nucleophiles is specifically limited to strong nucleophilic organolithiums and Grignard reagents, as well as phenolates.

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Section: Box 1 | Coordination Modes Of Co 2 With Transition Metalsmentioning

confidence: 99%

Using carbon dioxide as a building block in organic synthesis

et al. 2015

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“…[143][144][145][146][147][148][149][150][151][152][153] Due to its stereoregularity, it is highly crystalline (although there is no clear trend between % crystallinity and % ee of the polymer) with a T m greater than atactic PCHC (though the reported melting values have varied greatly). [143][144][145][146] The only systematic study relating T m to % ee showed a positive correlation (T m = 234-267 °C) between the properties for samples ranging from 78-99% ee. 143 On the other hand, syndiotactic-enriched PCHC has been qualitatively described as 'amorphous' but no thermal data was reported.…”

Section: Degradable Polymersmentioning

confidence: 99%

Stereochemical enhancement of polymer properties

et al. 2019

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The importance of stereochemistry to the function of molecules is generally well understood. However, to date, control over stereochemistry and its potential to influence properties of the resulting polymers are, as yet, not fully realised. This review focuses on the state-of-the-art with respect to how stereochemistry in polymers has been used to influence and control their physical and mechanical properties as well as begin to control their function. A brief overview of the synthetic methodology by which to access these materials is included, with the main focus directed towards stereochemical control over properties such as mechanical, biodegradation and conductivity. Additionally, the advances being made towards enantioseparation, enantioselective catalyst supports and stereo-directed transitions are discussed. Finally, we also consider the opportunities that the rich stereochemistry of sustainably-sourced monomers could offer in this field. Where possible, parallels and general design principles are drawn together to identify opportunities and limitations that these approaches may present in their effects on materials properties, performance and function.

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“…This catalyst catalyzed the asymmetric alternating copolymerization of carbon dioxide and cyclohexene oxide in quantitative yield and high enantioselectivity of up to 93.8% ee. 19 This enantioselectivity was much better than that of Trost's dinuclear zinc−ProPhenol catalyst in the same reaction. 20 This activity is because of the relatively rigid ligand skeleton and appropriate chiral microenvironment provided by the four-membered heterocycle.…”

Section: ■ Introductionmentioning

confidence: 92%

“…Although direct structural evidence for complex I could not be ascertained by electrospray mass spectral analysis or X-ray crystallography, previously similar work by Ding and coworkers suggests the formation of a dinuclear zinc ProPhenol complex, 20 and a dinuclear zinc−AzePhenol complex 2 could be captured by benzoic acid molecules recently reported by us. 19 Thus, we propose that the dinuclear zinc complex I is the real active catalyst species. The fact that N-benzylpyrrole (11b), N-benzoylpyrrole (11c), or N-methylpyrrole (11d) gives no reaction supports our guess.…”

Section: ■ Proposed Catalytic Mechanismmentioning

confidence: 99%

Enantioselective Friedel–Crafts Alkylation of Pyrrole with Chalcones Catalyzed by a Dinuclear Zinc Catalyst

et al. 2014

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A highly enantioselective Friedel-Crafts (F-C) alkylation of pyrrole with a wide range of simple nonchelating chalcone derivatives catalyzed by a chiral (Zn2EtL)n (L = (S,S)-1) complex has been developed. The catalyst (Zn2EtL)n complex was prepared in situ by reacting the chiral ligand (S,S)-1 with 2 equiv of diethylzinc. A series of β-pyrrole-substituted dihydrochalcones were usually formed mostly in excellent yields (up to 99%) and excellent enantioselectivity [up to 99% enantiomeric excess (ee)] by using 15 mol % catalyst loading under mild conditions. The absolute stereochemistry of the products was determined to be the S-configuration by X-ray crystallographic analysis of 13g. Meanwhile, a weak negative nonlinear effect was observed. On the basis of the experimental results and previous reports, a possible mechanism was proposed to explain the origin of the asymmetric induction.

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Highly Enantioselective Catalytic System for Asymmetric Copolymerization of Carbon Dioxide and Cyclohexene Oxide

Cited by 52 publications

References 69 publications

Using carbon dioxide as a building block in organic synthesis

Using carbon dioxide as a building block in organic synthesis

Stereochemical enhancement of polymer properties

Enantioselective Friedel–Crafts Alkylation of Pyrrole with Chalcones Catalyzed by a Dinuclear Zinc Catalyst

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