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A copper-catalyzed enantioselective fluoroalkenylation of cyclic imino esters was developed. Using this protocol, tetrasubstituted monofluoroalkenes bearing a quaternary center were afforded in good yields with high E/Z-selectivities and excellent enantioselectivities.

Calcineurin, a key regulator of the calcium signaling pathway, is involved in calcium signal transduction and calcium ion homeostasis. Magnaporthe oryzae is a devastating filamentous phytopathogenic fungus in rice, yet little is known about the function of the calcium signaling system. Here, we identified a novel calcineurin regulatory-subunit-binding protein, MoCbp7, which is highly conserved in filamentous fungi and was found to localize in the cytoplasm. Phenotypic analysis of the MoCBP7 gene deletion mutant (ΔMocbp7) showed that MoCbp7 influenced the growth, conidiation, appressorium formation, invasive growth, and virulence of M. oryzae. Some calcium-signaling-related genes, such as YVC1, VCX1, and RCN1, are expressed in a calcineurin/MoCbp7-dependent manner. Furthermore, MoCbp7 synergizes with calcineurin to regulate endoplasmic reticulum homeostasis. Our research indicated that M. oryzae may have evolved a new calcium signaling regulatory network to adapt to its environment compared to the fungal model organism Saccharomyces cerevisiae.

Herein we described the first enantioselective Cu/sulfoxide phosphine (SOP) complex catalyzed nucleophilic addition of fluorinated enolates to

Herein we report an enantioselective sulfenylation of cyclic imino esters with the efficient and versatile sulfenylation reagent S-alkyl 4-methylbenzenesulfonothioates. By utilizing the Cu/tBu-Phosferrox catalytic system, we can assemble diverse S-alkyl groups into the cyclic imino esters under mild conditions in good yields and with excellent enantioselectivities. Remarkably, this method demonstrates a high tolerance of diverse functional groups and proves to be applicable in the late-stage functionalization of pharmaceuticals.

A Pd-catalyzed hydrothiocarbonylation of unactivated terminal alkenes is presented. According to this protocol, aliphatic thioesters were synthesized with exclusive linear selectivity under mild reaction conditions. Good to excellent yields (up to 91% yield), broad substrate scope, broad functional group tolerance, and utility of the method demonstrated the advantages of this protocol.

Twelve new norspongian diterpenes, dinorspongians A–F (1–6) and epoxynorspongians A–F (7–12), were isolated from the marine sponge Spongia sp. Compounds 1–6 were the first examples of dinorspongian diterpenes bearing the unprecedented 3,4-seco-3,19-dinorspongian diterpene skeleton. Compounds 7–12 were the new 19-norspongian diterpenes possessing a 5,17-epoxy unit firstly. The structures with absolute configurations of these compounds were elucidated by the methods of NMR, X-ray diffraction and quantum chemical calculation. The biogenetic routes of 1–12 were also proposed, which suggested that the 19-norspongian diterpenes might be the intermediates of 3,4-seco-3,19-dinorspongian diterpenes. It was the first time to discuss the biosynthetic relationship between these two types of norspongian diterpenes. In addition, all the compounds were evaluated for their cytotoxic activities against several cancer cell lines. Compound 11 showed moderate activities against the PC3 and PBL-2H3 cell lines with IC50 values of 24.8 and 27.2 μM, respectively.

Two new halogenated metabolites, laurenhalogens A (1) and B (2), along with four known ones (3–6), were isolated from the red alga Laurencia sp. The structures of 1 and 2 were determined by the means of UV, IR, MS, NMR and X-ray diffraction analysis. In addition, the antibacterial activities of 1–6 were also evaluated.

Beauvercin H (1), a new cyclic hexadepsipeptide, and two known ones (2 and 3) were isolated from the EtOH extract of the solid culture of Fusarium sp. Their structures were elucidated by spectroscopic analysis, including extensive 1D and 2D NMR techniques, as well as comparison with literature values. Additionally, compounds 1–3 were tested for their cytotoxic activities. The results showed that all isolated compounds exhibited cytotoxic activities against five human cancer cell lines with IC50 values ranging from 1.379 to 13.12 μM.

As a special engineering material, poly(ether-ether-ketone) (PEEK) wires and cables are widely applied in the containment vessel of nuclear power plant and vulnerable to long-term cumulative effects of multiple complex factors. Wherein, thermo-oxidative aging in high temperature environment for a long time is the key factor to lead to the degradation even failure of PEEK cables. Therefore, in this work, PEEK cables were subjected to thermo-oxidative aging for different times at 310 °C and the effects on the physicochemical properties of PEEK were investigated. Furthermore, the aging life expectancy of PEEK cables was effectively predicted by the innovative artificial accelerated aging model with breaking elongation as evaluation parameter. The results revealed the thermal stability and crystallinity of PEEK samples declined significantly with the extension of aging time. Prolonged thermo-oxidative aging can accelerate the oxidation decomposition and change the sample morphologies. Moreover, the scratch resistance and bending strength of PEEK cables were significantly weakened after 480 h aging. The final prediction suggested that the service life expectancy of PEEK cable samples can reach 73 years at the working temperature of 90 °C.

(+)- and (−)-Spongiterpene [(+)-1 and (−)-1], a pair of new valerenane sesquiterpene enantiomers, along with four known compounds (2-5) were isolated from the marine sponge Spongia sp. The structures of (+)-1 and (−)-1 including absolute configurations were determined by spectroscopic analysis, quantum chemical calculation and X-ray diffraction. Compounds (+)-1 and (−)-1 were the first examples of valerenane sesquiterpenes isolated from the marine sponges. The cytotoxic activities of (+)-1 and (−)-1 were also evaluated.

Spongiains A-C (1–3), the first examples of spongian diterpenes bearing a pentacyclic skeleton composed of a fused 5/5/6/6/5 ring system through ring A rearrangement, together with four new spongian diterpenes, spongiains D-G (4–7), were isolated from the marine sponge Spongia sp.. The structures with absolute configurations of these compounds were elucidated by the methods of NMR, X-ray diffraction and quantum chemical approaches. The hypothetical biogenetic pathways as well as cytotoxic activities of 1–7 were also discussed.

A new Cu-catalyzed enantioselective three-component (i.e., styrenes, B2pin2, and propargylic phosphates) allenylation via an SN2' substitution of propargylic electrophiles with vinylarene-derived chiral nucleophiles is presented. This method provides an efficient and enantioselective approach to access a range of optically pure di-(1,1-), tri-, and tetra-substituted allenes with α-central chirality and axial chirality in excellent chemo-, regio-, diastereo-, and enantioselectivities.

In maize, the ear shank is a short branch that connects the ear to the stalk. The length of the ear shank mainly affects the transportation of photosynthetic products to the ear, and also influences the dehydration of the grain by adjusting the tightness of the husks. However, the molecular mechanisms of maize shank elongation have rarely been described. It has been reported that the maize ear shank length is a quantitative trait, but its genetic basis is still unclear. In this study, RNA-seq was performed to explore the transcriptional dynamics and determine the key genes involved in maize shank elongation at four different developmental stages. A total of 8145 differentially expressed genes (DEGs) were identified, including 729 transcription factors (TFs). Some important genes which participate in shank elongation were detected via function annotation and temporal expression pattern analyses, including genes related to signal transduction hormones (auxin, brassinosteroids, gibberellin, etc.), xyloglucan and xyloglucan xyloglucosyl transferase, and transcription factor families. The results provide insights into the genetic architecture of maize ear shanks and developing new varieties with ideal ear shank lengths, enabling adjustments for mechanized harvesting in the future.

A new amide, baeriamide (1), along with nine known diketopiperazines (2-10), was isolated from the marine sponge Haliclona baeri. Their structures were identified by the means of UV, IR, MS and NMR. The absolute configuration of 1 was established by Marfey's method and comparing the specific optical rotation with the known compound HCO-Val-Gly methyl ester. Compound 1 was derived from dehydration of formylated L-valine with γ-amino-butanoic acid methyl ester. Compounds 2-10 were isolated from the genus of Haliclona for the first time. The absolute confirmation of 7 was confirmed first by the means of single-crystal X-ray diffraction. The cytotoxic, antibacterial, antiviral and antifouling activities of these compounds were also tested. However, none of them exhibited significant bioactivities.

A new polyketide, solieritide A (1), along with six known ones (2–7), had been isolated from the red alga Solieria sp. The structures of these compounds were elucidated by spectroscopic analysis. The absolute configuration of 1 was determined by the method of X-ray diffraction. Compound 1 was a rare polyketide bearing benzopyrone ring fused with γ-butyrolactone. Compounds 2–7 were isolated from the red algae of genus Solieria for the first time. The antibacterial activities of 1–7 were also discussed.

Two new pyrrolidine alkaloids, acanthophoraines B (1) and C (2), together with five known ones (3–7) were isolated from the red alga Acanthophora spicifera. Their structures were elucidated by extensive spectroscopic methods and single-crystal X-ray diffraction analysis. The absolute configuration of 2 was established by ECD calculation. The antibacterial activities of 1–7 were also evaluated.

Two new furandione derivatives, designated as asperfurandiones A (1) and B (2), were isolated from the solid culture of the marine-derived fungus Aspergillus versicolor. Their structures were elucidated using a combination of mass spectrometry and NMR spectroscopy. Additionally, asperfurandiones A and B both showed moderate antifungal activity against Gaeumannomyces graminis, Cryptococcus neoformans, and Candida albicans with MIC values of 64 μg/mL.

A new α-pyrone, nocapyrone S (1), together with five known compounds (2-6), were isolated from the deep-sea actinomycete Nocardiopsis dassonvillei subsp. dassonvillei DSM 43111(T). Their structures were determined by spectroscopic analyses. The absolute configuration of 1 was established by quantum approaches. Cytotoxic activity of 1 was evaluated against K562, MCF-7, SGC7901, A375, Hela, and HepG2 cell lines.

A solvent-assisted vacuum desorption method is developed and combined with gas chromatography-tandem mass spectrometry (GC-MS/MS) for quick determination of soil PAHs. With the assistance of a reduced pressure of 0.0001 kPa and the DMSO/acetone (1:1) mixed solvent, this method allows desorption of PAHs in a moderate temperature of 160 °C. Analytes were trapped in a collection tube and eluted with n-hexan for GC-MS/MS analysis. The entire procedure can be completed within 20 min. In order to validate this method for determining soil PAHs, the solvent-assisted vacuum desorption method, Soxhlet extraction and ASE extraction were applied in different samples of real contaminated soils. Most HMW PAHs showed similar concentrations, yet LMW PAHs with solvent-assisted vacuum desorption presented significantly higher concentrations than those with conventional methods, such as NAP, ANY, ANA and FLU. Further investigation revealed that solvent-assisted vacuum desorption is capable of improving both the extractability and collection efficiency of those four LMW PAHs in real contaminated soil. This method enables desorption of HMW PAHs and provides the additional benefit of improved extractability and collection efficiency for LMW PAHs.

A new thiodiketopiperzaine, tedanizaine A (1), together with six known ones, were isolated from the marine sponge Tedania sp. Their structures were determined by spectroscopic analyses. The absolute configuration of 1 was established by ECD calculation. Compound 1 was the second example of thiodiketopiperazine bearing a thiazolidine unit. Cytotoxic activities of 1 were also evaluated.

A new pyrrolidine alkaloid, acanthophoraine A (1), along with six known alkaloids (2–7), had been isolated from the red alga Acanthophora spicifera. The structures of these compounds were identified by spectroscopic analyses. The absolute configuration of 1 was established by ECD calculation. Compound 1 represents the first example of N-isobutyl pyrrolidone with an urea arm. The antimicrobial activity of 1 was also evaluated.

A Cu-catalyzed diastereo- and enantioselective borylative coupling reaction of 1,3-dienes with imines was realized. Branched homoallylic amines are readily prepared in a syn-selective manner with high regio-, diastereo- and enantioselectivity. Moreover, these three-component coupling reactions feature good functional-group compatibility and easy access to the substrates and catalyst.

Three new cyclohexadepsipeptides, oryzamides A-C (1-3), two isolation artifacts, oryzamides D (4) and E (5), and the known congener scopularide A (6), all possessing a rare 3-hydroxy-4-methyldecanoic acid (HMDA) substructure, were isolated from the mycelial extract of the sponge-derived fungus Nigrospora oryzae PF18. Their planar structures were elucidated by spectroscopic analysis and comparison with the literature data. The absolute configurations were determined using the advanced Marfey's method and single-crystal X-ray diffraction analysis. Among them, oryzamides D (4) and E (5) were a pair of diastereomers at the sulfur atom of the l-methionine sulfoxide residue, which showcased the possible separation of a pair of methionine sulfoxide diastereomers. The X-ray crystal structure of scopularide A (6) was obtained for the first time, thereby establishing its relative and absolute configuration at C-4 of the HMDA residue. Oryzamides A-C (1-3) did not display cytotoxic, antibacterial, antiparasitic, and NF-κB inhibitory activities.

A new sesquiterpene named menecubebane B (1) and a known analogue (2) were isolated from the gorgonian coral Menella sp. Their structures were elucidated by the extensive analyses of spectroscopic data and by the comparison with related literature. Cytotoxic effect against both Eca9706 and HeLa cell lines was evaluated, revealing 1 exhibited moderate cytotoxicity against the two cell lines involved with IC50 values being 20.8 and 30.6 μM, respectively.

A step-wise reductive method that converts nonracemic γ-chiral α-ketoamides into amide derivatives was developed under mild conditions. The method involves a highly efficient three-step transformation including NaBH4-reduction, bromination and Pd/C hydrogenation reactions. As a consequence, a variety of nonracemic γ-diaryl amides products were obtained in high overall yields with excellent enantiomeric specificity. The utility of the method is demonstrated through the concise formal synthesis of (+)-sertraline in good overall yield.

The total synthesis of reniochalistatins A-E, along with a reniochalistatin E analogue (inverso-E) was successfully achieved through Fmoc-based solid-phase peptide synthesis and subsequent macrolactamization with PyBOP and DIEA. The biological activities of these reniochalistatins and a key linear peptide intermediate were systematically evaluated. Among these seven synthesized compounds, linear reniochalistatin B was found to have potent activity against several cancer cell lines not shown by the cyclic reniochalistatin B counterpart. In addition, linear reniochalistatin B was found to have antitubercular activity (IC50 =1.4 μm). Inverso-E possesses increasing cytotoxicity against the HeLa and LNCaP cell lines after simple alternation of the sequence of amino acids in reniochalistatin E. The results of these studies provide a feasible method to further investigate the structure-activity relationships (SARs) of reniochalistatins A-E.

A novel valerenane sesquiterpenoid sinulaspirolactam A (1), together with five known compounds, was isolated from the soft coral Sinularia sp. Their structures were determined by spectroscopic analyses. The absolute configuration of 1 was established by ECD calculation. Compound 1 was the first example of valerenane sesquiterpenoid bearing an aza-spiro[4.5] ring moiety, the plausible biogenetic pathway of which was proposed. Cytotoxic activities of these compounds were also evaluated.

An enantioselective Cu-catalyzed borylative cross-coupling reaction of alkenes, bis(pinacolato)diboron (B2(pin)2), and methyl iodide is reported. Alkenes including styrenes, β-substituted styrenes, and challenging aliphatic olefins were smoothly transferred to the desired methylboration products with excellent diastereoselectivities (dr up to >99:1) and enantioselectivities (er up to 99:1). The utility of this process was demonstrated by the synthesis of naproxen and formal synthesis of two natural products.

Presented is the first enantioselective copper-catalyzed 1,6-conjugate addition of bis(pinacolato)diboron to para-quinone methides. The reaction proceeds with excellent yields and good to excellent enantioselectivities, and provides an attractive approach to the construction of optically active gem-diarylmehtine boronic esters. Additionally, the subsequent conversion of the derived potassium trifluoroborates into triarylmethanes with highly enantiospecificity was realized.

Nine new 9,11-secosterols (1-9), containing the same 3β,6α,11-trihydroxy-9,11-seco-5α-cholest-7-en-9-one steroidal nucleus, whereas possessing an array of structurally diverse side chains, along with fourteen known 9,11-secosterol compounds (10-23), were isolated from the South China Sea gorgonian coral Subergorgia suberosa, of which 3/4, 5/6, 7/8, and the known compounds 11/12, 20/21 were five pairs of inseparable C-24 epimers. Their structures were established by the extensive analyses of 1D and 2D NMR spectra, high-resolution chemical ionization mass spectrometry (HRCIMS), and by the comparison with literature data. Cytotoxic effect of these metabolites against the growth of HeLa cell lines was evaluated. The result showed that the inhibitory effect of compounds 1-23 varied considerably depending on the nature of the side chain in spite of sharing the same steroidal nucleus. Compound 19, featuring both the absence of hydroxyl group and the presence of double bond in the stigmasterol side chain, exhibited the most potent cytotoxicity with IC50 being 15.1 μM. The preliminary structure activity relationship studies identified some important structural features considerably influencing the biological effect deserved, providing valuable information for chemists and pharmacologists to design and synthesize more effective antitumor agents bearing the 9,11-secosteroid framework.

A new alkaloid named N-(3-aminopropyl)subergorgamide (1), along with nine known nitrogen-containing compounds (2-10), was isolated from the organic extract of gorgonian Paraplexaura sp. collected from Zhanjiang in Naozhou Island, South China Sea. Their structures were established by detailed MS and NMR spectroscopic analyses, as well as by comparison with literature data.

Palladium-catalyzed asymmetric intermolecular hydroalkoxylation of allenes has been developed by using phenol as a pronucleophile. Acyclic O,O-acetals were obtained in high yields (up to 98%) with good to excellent enantiomeric excesses (up to 94% ee).

Garlic (Allium sativum L.), which is a widely distributed plant, is globally used as both spice and food. This study identified five novel phenolic compounds, namely, 8-(3-methyl-(E)-1-butenyl)diosmetin, 8-(3-methyl-(E)-1-butenyl)chrysin, 6-(3-methyl-(E)-1-butenyl)chrysin, and Alliumones A and B, along with nine known compounds 6-14 from the ethanol extract of garlic. The structures of these five novel phenolic compounds were established via extensive 1D- and 2D-nuclear magnetic resonance spectroscopy experiments. The effects of the phenolic compounds isolated from garlic on the enzymatical or nonenzymatical formation of sulfur-containing compounds produced during garlic processing were examined. Compound 12 significantly reduced the thermal decomposition of alliin, whereas compound 4 exhibited the highest percentage of alliinase inhibition activity (36.6%).

Two new polyketides, aspergchromones A (1) and B (2), together with five known compounds, secalonic acid D (3), noreugenin (4), (3S)-5-hydroxymellein (5), (4S)-6-hydroxyisosclerone (6), and (-)-regiolone (7), were isolated from the ethyl acetate extract of marine sponge-derived fungus Aspergillus sp. SCSIO XWS03F03. Their structures were elucidated by means of spectroscopic techniques (1D and 2D NMR, MS, UV, and IR). The absolute configurations of the new compounds were established by ECD calculations. Compound 3 showed moderate antimicrobial activity.

Background Methylenetetrahydrofolate reductase gene (MTHFR C677T and A1298C) and methionine synthase gene (MS A2756G) polymorphisms have shown an association with male infertility risk in several ethnic populations. Although several studies have evaluated these associations in Chinese populations, their small sample sizes and inconsistent outcomes have prevented strong conclusions. Therefore, the present meta-analysis was performed with published studies to evaluate the associations of the three single nucleotide polymorphisms (SNPs) and male infertility in a Chinese population. Methods We conducted a search of PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), China biology medical literature (CBM), VIP, and Chinese literature (Wan Fang) databases up to May 31, 2016. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were used to assess the strength of associations with a random-effect model or a fixed-effect model based on the heterogeneity analysis results. Sensitivity analysis was used to confirm the reliability and stability of the meta-analysis. Results A total of nine studies, including 1,713 cases and 1,104 controls, were included in the meta-analysis. The pooled results indicated that the MTHFR C667T polymorphism was significantly associated with increased risk of male infertility in the Chinese population in the allele model (T vs. C: OR = 1.47, 95%CI = 1.32–1.63), the dominant model (TT + CT vs. CC: OR = 1.51, 95%CI = 1.30–1.77), the additive model (TT vs. CC: OR = 2.08, 95%CI = 1.68–2.58) and the recessive model (TT vs. CT+CC: OR = 1.58, 95%CI = 1.31–1.90), whereas the MTHFR A1298C and MS A2756G polymorphisms were not risk factors. There was no significant heterogeneity in any genotype contrasts among the studies. The sensitivity analysis indicated that the results of this meta-analysis were relatively stable. Conclusion This study suggests that the MTHFR C667T polymorphism may contribute to the genetic susceptibility to male infertility in the Chinese population, whereas MTHFR A1298C and MS A2756G polymorphisms may be unrelated to male infertility. Studies with larger sample sizes and representative population-based cases and well-matched controls are needed to validate our results.

Rh-Catalyzed asymmetric 1,4-selective addition of arylboronic acids to beta,gamma-unsaturated alpha-keto ester was developed using chiral tert-butanesulfinylphosphine as ligand, good yields (up to 87%), good 1,4-regioselectivities (up to 96:4), and high enantioselectivities (up to 94% ee) were achieved. (C) 2014 Elsevier Ltd. All rights reserved.

A novel unusual pentacyclic hemiacetal sterol nephthoacetal (1), was isolated from soft coral Nephthea sp. The structure of this sterol was inferred from its two acetyl derivatives (2) and (3), by means of spectroscopic methods, and quantum chemical calculations. Anti-fouling activity of compounds 1-3 against Bugula neritina larvae was evaluated, sterol (1) exhibited significant inhibitory effect with EC(50) value of 2.5 μg/mL, while having low toxicity with LC(50)>25.0 μg/mL. The in vitro cytotoxic activity of compounds 1-3 against HeLa cells was also evaluated, all of them exhibited moderate cytotoxicity with IC(50) values of 12.3 (1), 10.1 (2), and 19.6 μg/mL (3), respectively.

A step-wise reductive method that converts nonracemic γ-chiral α-ketoamides into amide derivatives was developed under mild conditions. The method involves a highly efficient three-step transformation including NaBH4-reduction, bromination and Pd/C hydrogenation reactions. As a consequence, a variety of nonracemic γ-diaryl amides products were obtained in high overall yields with excellent enantiomeric specificity. The utility of the method is demonstrated through the concise formal synthesis of (+)-sertraline in good overall yield.

In continuation of our search for new antibacterial and antioxidant metabolites from sponge-derived fungi, one new tyrosol derivative, hypocrol A (1), together with four known congeners, trichodenol B (2), 4-hydroxyphenethyl acetate (3), 4-hydroxyphenethyl tetradecanoate (4) and 1-oleyltyrosol (5), was isolated from the strain Hypocrea koningii PF04. Their planar structures were unequivocally elucidated by spectroscopic methods and comparison with the literature data. All the compounds displayed weak antibacterial activities against Staphylococcus aureus, methicillin-resistant S. aureus and Escherichia coli, whereas compounds 1 and 2 exhibited a moderate antioxidant efficacy in the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay with IC50 values of 48.5 and 97.4 μg/mL, respectively.

A new polyhydroxysterol, (22E)-24-methylenecholestane-22-ene-3β,5α,6β-triol (1), together with four known analogues (2–5) were isolated from the South China Sea soft coral Sinularia sp. Their structures were elucidated by spectroscopic analyses and comparison with previously reported data. All these compounds exhibited cytotoxic effect against both HepG2 and HeLa cell lines with IC50 values ranging from 8.36 to 37.30 μM. Preliminary structure–activity relationship study identified that the presence of double bonds in the side chains of these polyhydroxysterols significantly reduced the biological effect obtained.

A general method to obtain enantioenriched 1,3,3-triarylpropan-1-ones bearing a diarylmethine stereocenter was developed using Rh/chiral sulfinylphosphine catalyzed 1,4-addition of arylboronic acids to chalcones. The catalysis progressed smoothly in the presence of 2 mol % catalyst formed in situ from [Rh(C2H4)(2)Cl](2) and chiral tert-butanesulfinylphosphine and gave the adducts with up to 99% yield and 98% ee. (C) 2012 Elsevier Ltd. All rights reserved.

A new flexible C1-symmetric tridentate ligand (S)-N-(2-(tert-butylsulfinyl)benzyl)-1-(pyridin-2-yl)methanamine sulfoxide (L1) was successfully prepared and utilized as a chiral ligand for Ir(I)-catalyzed ATH (asymmetric transfer hydrogenation) reactions. Without any cooperation of other chiral center, encouraging ee and conversion values have been achieved, which provide us a better understanding on these types of ligands and a new strategy to develop new high-efficiency chiral catalysts for asymmetric reaction.

Self-assembling cyclic peptide nanotubes (SPNs) have been extensively studied due to their potential applications in biology and material sciences. Cyclic γ-peptides, which have a larger conformational space, have received less attention than the cyclic α- and β-peptides. The self-assembly of cyclic homo-γ-tetrapeptide based on cis-3-aminocyclohexanecarboxylic acid (γ-Ach) residues, which can be easily synthesized by a one-pot process is investigated. Fourier transform infrared (FTIR) and NMR analysis along with density functional theory (DFT) calculations indicate that the cyclic homo-γ-tetrapeptide, with a non-planar conformation, can self-assemble into nanotubes through hydrogen-bond-mediated parallel stacking. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) experiments reveal the formation of bundles of nanotubes in CH2Cl2/hexane, but individual nanotubes and bundles of only two nanotubes are obtained in water. The integration of TEG (triethylene glycol) monomethyl ether chains and cyclopeptide backbones may allow the control of width of single nanotubes.

A class of chiral sulfoxide-olefins were designed and synthesized through concise routes. Their applications as ligands in Hayashi-Miyaura reaction were studied, which found that vinyl substituents of the ligands vary in stereocontrolling ability. Particularly, either isomer of adducts with excellent ees could be readily obtained through changing the position of the substituents of olefins as well as changing the configuration of the C=C bond of the ligands. Meanwhile, the substrate scope of arylboronic acids and alkenes was clearly shown. (C) 2012 Elsevier Ltd. All rights reserved.

A chiral titanium complex, formed in situ from Ti(Oi-Pr)4, (S,S)-N,N′-dibenzyl tartramide and water was found to serve as an efficient catalyst for the asymmetric oxidations of 1H-benzimidazolyl pyridinylmethyl sulfides with cumene hydroperoxide (CHP) in the absence of a base. Several proton pump inhibitors (PPIs), such as esomeprazole, lansoprazole, rabeprazole and pantoprazole were obtained in high yield (up to 92%) and excellent enantiomeric excess (up to 96%).

The transition metal-catalyzed asymmetric variant of the title reaction is normally limited to N-protected isatins. However, Rh(I)/chiral sulfoxide phosphine complexes were found to catalyze the enantioselective addition of arylboronic acids to NH isatins under mild conditions. A variety of chiral 3-aryl-3-hydroxyl-2-oxindoles were obtained with high yields and with good to excellent enantioselectivities (85–92% ee).