Highly enantioselective olefin epoxidation controlled by helical confined environments

Fernandes, Cristina I.; Saraiva, Marta S.; Nunes, Teresa; Vaz, Pedro D.; Nunes, Carla D.

doi:10.1016/j.jcat.2013.08.032

Cited by 42 publications

(22 citation statements)

References 67 publications

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“…The course of the reactions was monitored by quantitative GC-MS analysis by collecting samples at 10, 30 min, 1 and 1.5 h, then at 2, 4, 6, 8, and 24 h of reaction. These samples were treated as described previously prior to injection in the GC column [20][21][22].…”

Section: Catalytic Testsmentioning

confidence: 99%

Catalytic Application of Fe-doped MoO2 Tremella-Like Nanosheets

et al. 2016

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MoO 2 nanoparticles with tremella-like morphology have been synthesized and characterized. Characterization by powder X-ray diffraction (XRD) and transmission electron micrographs (TEM) microscopy made possible to estimate that the nanosheets have ca. 12 nm and aggregate to form tremella-like structures. The resulting MoO 2 nanoparticles were used as catalyst for epoxidation of several olefins. The use of tert-butylhydroperoxide (tbhp), H 2 O 2 and cumenehydroperoxide (chp) as oxygen sources was screened under different reaction conditions, namely, solvent and temperature. The results from the catalytic experiments show that this catalyst was very efficient leading to very high conversion and product selectivity levels. In addition, the use of oxidant:olefin ratios close to 1 show that this catalyst is very efficient conducting olefin epoxidation. Further details are discussed in the work. The catalyst showed overall excellent performance with tbhp. When using H 2 O 2 , the catalyst showed good activity, which is very relevant as well. All these achievements contribute with a step forward in the development of more environmentally friendly processes.

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Section: Catalytic Testsmentioning

confidence: 99%

Catalytic Application of Fe-doped MoO2 Tremella-Like Nanosheets

et al. 2016

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“…Actually, chiral centers of ribofuranose were hydroxylated and centralized, which were prone to inter-or intramolecular hydrogen bonds, eventually facilitating enantioselectivity. On the other hand, some nanosized helical silica had been applied as support in asymmetric catalysis [14], which confirmed chiral induction of helical configuration. Based on these progresses, this work aimed to develop helical silica for immobilization of guanosine as organocatalyst in asymmetric hetero-Diels-Alder reaction, and to test synergetic effects between molecular catalyst and support.…”

Section: Introductionmentioning

confidence: 88%

Silica-based helical rod supporting guanosine compounds catalyzed asymmetric hetero-Diels–Alder reaction

Zhang

Huang

et al. 2015

Catalysis Communications

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“…In HKR of styrene oxide, CoB3 showed distinguished major configurations for two resolution products due to (S,S)-configuration of Co-salen at homogeneous level (entries 15 vs. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] [41]. Particularly, HB6 showed two major configurations contrary to CoB3 (entries 20 vs. 15).…”

Section: Catalytic Hydrolytic Kinetic Resolution Of Epoxidesmentioning

confidence: 99%

“…But interestingly, non-chiral templates could provide helical materials too [16,17]. Recently, Vaz and Nunes proved helical silica had excellent chiral recognition based on their combination with non-chiral molybdenum complexes in catalytic asymmetric epoxidation [18]. Therefore, synthesis of helical materials was feasible, and chiral induction of these materials might be applied in many other fields.…”

Section: Introductionmentioning

confidence: 99%

Macroporous Helical Silica Immobilizing Cobalt-Salen Complex Catalyzed Asymmetric Hydrolytic Kinetic Resolution of Epoxides

Huang

Liu

et al. 2015

Catal Surv Asia

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Based on an entropy-driven principle, new macroporous helical silica rods were synthesized by using mild templates in sol-gel, then functionalized for immobilizing Co-salen complexes to catalyze enantioselective hydrolytic kinetic resolution of epoxides. Characterization revealed both silica supports and heterogeneous Co-salen complexes were macroporous helical materials with affirmative chirality. Catalysis revealed enantioselective adsorption of substrate on silica supports dominated major configuration of resolution products rather than configuration of Co-salen. The (S)-amino alcohol-doped silica and Co-(R,R)salen comprised the most enantioselective combination, which proved chiral synergy between support and Co-salen did exist. This work would contribute to the design of new support materials for asymmetric catalysis.

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Highly enantioselective olefin epoxidation controlled by helical confined environments

Cited by 42 publications

References 67 publications

Catalytic Application of Fe-doped MoO2 Tremella-Like Nanosheets

Catalytic Application of Fe-doped MoO2 Tremella-Like Nanosheets

Silica-based helical rod supporting guanosine compounds catalyzed asymmetric hetero-Diels–Alder reaction

Macroporous Helical Silica Immobilizing Cobalt-Salen Complex Catalyzed Asymmetric Hydrolytic Kinetic Resolution of Epoxides

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