Single-Electron Oxidation-Initiated Enantioselective Hydrosulfonylation of Olefins Enabled by Photoenzymatic Catalysis.

Controlling the enantioselectivity of hydrogen atom transfer (HAT) reactions has been a long-standing synthetic challenge. While recent advances on photoenzymatic catalysis have demonstrated the great potential of non-natural photoenzymes, all of the transformations are initiated by single-electron reduction of the substrate, with only one notable exception. Herein, we report an oxidation-initiated photoenzymatic enantioselective hydrosulfonylation of olefins using a novel mutant of gluconobacter ene-reductase (GluER-W100F-W342F). Compared to known photoenzymatic systems, our approach does not rely on the formation of an electron donor-acceptor complex between the substrates and enzyme cofactor and simplifies the reaction system by obviating the addition of a cofactor regeneration mixture. More importantly, the GluER variant exhibits high reactivity and enantioselectivity and a broad substrate scope. Mechanistic studies support the proposed oxidation-initiated mechanism and reveal that a tyrosine-mediated HAT process is involved.

Adaptive evolution driving the young duplications in six Rosaceae species.

BACKGROUND: In plant genomes, high proportions of duplicate copies reveals that gene duplications play an important role in the evolutionary processes of plant species. A series of gene families under positive selection after recent duplication events in plant genomes indicated the evolution of duplicates driven by adaptive evolution. However, the genome-wide evolutionary features of young duplicate genes among closely related species are rarely reported. RESULTS: In this study, we conducted a systematic survey of young duplicate genes at genome-wide levels among six Rosaceae species, whose whole-genome sequencing data were successively released in recent years. A total of 35,936 gene families were detected among the six species, in which 60.25% were generated by young duplications. The 21,650 young duplicate gene families could be divided into two expansion types based on their duplication patterns, species-specific and lineage-specific expansions. Our results showed the species-specific expansions advantaging over the lineage-specific expansions. In the two types of expansions, high-frequency duplicate domains exhibited functional preference in response to environmental stresses. CONCLUSIONS: The functional preference of the young duplicate genes in both the expansion types showed that they were inclined to respond to abiotic or biotic stimuli. Moreover, young duplicate genes under positive selection in both species-specific and lineage-specific expansions suggested that they were generated to adapt to the environmental factors in Rosaceae species.

An efficient, green, and easy-to-scale-up strategy for target-oriented isolating cadinene sesquiterpenoids from Eupatorium adenophorum Spreng.

A green and efficient strategy was established and optimized for target-oriented extraction, enrichment and separation of cadinene sesquiterpenoids from Eupatorium adenophorum Spreng., using the combination of supercritical fluid extraction, molecular distillation, and industrial preparative chromatography for the first time. The extraction conditions of supercritical fluid extraction were initially optimized by orthogonal experimental design. Under the optimum conditions, the contents of 9-oxo-10,11-dehydroageraphorone and 10Hß-9-oxo-ageraphorone, which were 55.00% and 6.01%, respectively, were much higher than conventional extraction methods. Then, the molecular distillation enrichment method was established and investigated by response surface methodology technology, which showed strong specificity for enriching target compounds and removing impurities from crude extracts. Under the optimum conditions of molecular distillation, total contents of cadinene sesquiterpenoids were increased to 89.19%. Finally, a total of 146 mg of 9-oxo-10,11-dehydroageraphorone and 29 mg of 10Hß-9-oxo-ageraphorone were easily obtained by industrial preparative chromatography, from 200 mg of distillation fraction, with purities over 99%. The contents of target components were analyzed by HPLC, and structures of them were identified by high-resolution MS, 1 H-NMR, and 13 C-NMR spectroscopy. These results indicate that it is a simple, effective, and eco-friendly strategy, which is easily converted into industrial scale.

Deracemization Enabled by Visible-Light Photocatalysis.

Deracemization is an ideal but challenging strategy for the conversion of a racemic mixture into a single enantiomer. Recent studies have demonstrated that visible-light photocatalysis could be utilized to promote selective deracemization of axially chiral allenes as well as cyclopropylquinolones and cyclic ureas with central chirality either through energy transfer or through a sequence of electron, proton, and hydrogen-atom transfer.

Straightforward Synthesis of Bifunctional Phosphorus Phenols via Phosphination of In Situ Generated o-Quinone Methides.

An efficient and practical approach towards bifunctional phosphorus phenols has been developed through a reaction of diphenylphosphine oxide and the o-quinone methides in situ generated from 2-tosylalkyl phenols under basic conditions. This protocol features simple experimental procedures under mild conditions and is easily scaled up. With this method, a variety of diarylmethyl phosphine oxides can be produced with up to 92% yield.

Ganoderin A, a novel 9,11-secosterol from Ganoderma lucidum spores oil.

In this study, four sterols were isolated from the Ganoderma lucidum spores oil obtained via supercritical CO2 extraction. Four chemical constituents were ganoderin A (1), chaxine B (2), ergosterol, (3) and stellasterol (4). All the separated ingredients were characterized using spectral data interpretation and by comparing with reported data. Noticeably, stellasterol and chaxine B were both firstly isolated from Ganoderma lucidum spores oil and ganoderin A was shown to bear an unprecedented skeleton.

Visible-light mediated catalytic asymmetric radical deuteration at non-benzylic positions.

Site- and enantioselective incorporation of deuterium into organic compounds is of broad interest in organic synthesis, especially within the pharmaceutical industry. While catalytic approaches relying on two-electron reaction manifolds have allowed for stereoselective delivery of a formal deuteride (D-) or deuteron (D+) at benzylic positions, complementary strategies that make use of one-electron deuterium atom transfer and target non-benzylic positions remain elusive. Here we report a photochemical approach for asymmetric radical deuteration by utilizing readily available peptide- or sugar-derived thiols as the catalyst and inexpensive deuterium oxide as the deuterium source. This metal-free platform enables four types of deuterofunctionalization reactions of exocyclic olefins and allows deuteration at non-benzylic positions with high levels of enantioselectivity and deuterium incorporation. Computational studies reveal that attractive non-covalent interactions are responsible for stereocontrol. We anticipate that our findings will open up new avenues for asymmetric deuteration.

Insights into modified red mud for the selective catalytic reduction of NOx: Activation mechanism of targeted leaching.

Red mud (RM) is a solid waste rich in iron oxide, which has the potential to be utilized as the catalyst for selective catalytic reduction (SCR) of NOx. We pretreated the RM sample with the selective acid leaching method, after which 97.6 % of the alkali was neutralized, and only 8 % of the Fe2O3 were leached out. Once leached, the RM samples were activated for the SCR reaction. It showed NOx conversions above 90 % in 310-430 °C and exhibited high resistance to SO2 and H2O. After leaching, i. the SBET reached twice as before; ii. the sintering caused by alkali was eliminated; iii. the activated RM exhibited improved Fe3+/Fe2+ ratio and enhanced chemisorbed surface oxygen (Oα); iv. the oxygen mobility and the surface acidity were promoted. Overall, the selective acid leaching is an efficient method to activate RM for the SCR reaction. The RM based catalysts can be an alternative for SCR technology.

Homogenate-assisted high-pressure disruption extraction for determination of phenolic acids in Lonicerae Japonicae Flos.

An effective method based on the combined homogenate-assisted high-pressure disruption extraction (HHPDE) was applied to the extraction and determination of the main phenolic acid compounds from Lonicerae Japonicae Flos. The optimized HHPDE showed competitive advantage in yield (The extraction yields of NCA, CA, 3,5DCA and 4,5DCA in HHPDE were 1.21, 1.08, 1.06 and 1.17 fold higher than those in UAE), time-saving (<5 min) and relative low temperature requirement (4-16 °C) compared to HRE and UAE. Furthermore, the HHPDE method behaved a good repeatability and reproducibility according to the HPLC. The mentioned HHPDE method is firstly applied in the extraction and quantification of neochlorogenic acid chlorogenic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid in Lonicerae Japonicae Flos. This work provided an excellent alternative for the extraction and quantification of thermosensitive from plants.

[Supercritical CO2 extraction of fatty oils from bee pollen and its GC-MS analysis].

The extraction of fatty oils from bee pollen with supercritical CO2 was studied. The effects of extraction pressure, extraction temperature and the grinding size of the bee pollen on the yields were discussed. The optimal condition of this method was: extraction pressure 30MPa,extraction temperature 55 degrees C, separator I pressure 14MPa, separator I temperature 45 degrees C, separator II pressure 6MPa, separator II temperature 40 degrees C, extraction period 2 hours. Compared with the traditional solvent extraction, this method had some virtues, such as shortening the extraction period greatly, escaping oxidation of unsaturated fatty acid, and the products from which having better quality. With a GC-MS analysis, the main composition of the fatty oil from the bee pollen was: oleic acid, palmitic acid, linoic acid, pentacosane, octacosane and so on. The contents of alpha-linolenic acid in the fatty oils from separator I and separator II were 42% and 8.8%, which differed greatly. It proved that this method succeeded in extraction, separating and enriching alpha-linolenic acid.

[Study on extraction of active ingredients from Andrographis paniculatal using the orthogonal experiment with supercritical carbon dioxide].

This paper studied the extraction technology of active ingredients from Andrographis paniculatal using the orthogonal experiment with supercritical CO2. The active ingredients of this extract had higher purity and more stable quality than those came from conventional extract technology. And the target ingredients, dehydrated andrographolidume and andrographolidume, had higher content. Furthermore this method had shorter technology process and saved a great deal of solvent than conventional ethanol extraction, which was exactly suitable for industrialization manufacture. The optimization condition was: extractor pressure 25 MPa, extractor temperature 46 degrees C, separator I pressure 6 MPa, separator I temperature 65 degrees C, separator II pressure 6 MPa, separator II temperature 45 degrees C, CO2 rate of flow 40 kg/h.