The complete plastid genome and characteristics analysis of Achillea millefolium.

Achillea is a crop with Chinese herbal characteristics and horticultural values. Its leaves and flowers contain aromatic oil, and the ripe herb can also be used as medicine to induce sweat and relieve rheumatic pains. It is seen cultivated in gardens all over China. Currently, the most comprehensive chloroplast genome sample involved in the study refers to New World clades of Achillea, which are used for marker selection and phylogenetic research. We completely sequenced the chloroplast genomes of Achillea millefolium. These sequencing results showed that the plastid genome is 149,078 bp in size and possesses a typical quadripartite structure containing one large single copy (LSC) with 82,352 bp, one small single copy (SSC) with 18,426 bp, and a pair of inverted repeat (IR) regions with 24,150 bp in Achillea millefolium. The chloroplast genome encodes a common number of genes, of which 88 are protein-coding genes, 37 transfer ribonucleic acid genes, and 8 ribosomal ribonucleic acid genes, which are highly similar in overall size, genome structure, gene content, and sequence. The exact similarity was observed when compared to other Asteraceae species. However, there were structural differences due to the restriction or extension of the inverted repeat (IR) regions-the palindromic repeats being the most prevalent form. Based on 12 whole-plastomes, 3 hypervariable regions (rpoB, rbcL, and petL-trnP-UGG) were discovered, which could be used as potential molecular markers.

Diversified-profit maximization in competitive social advertising.

Due to the important role that social networks play in advertisements and propaganda, influence maximization (IM) problem which aims at finding some influential users as seeds to trigger large online cascading influence spread has been a hot research topic in the past two decades. As an extension of classical IM problem, profit maximization (PM) problem is inspired by product promotion and focuses on the profit generated by consumer. Given that competitive social advertising is more common in real-world, a series of studies propose some versions of PM problem. However, the competition happening in the information dissemination of imperfect substitutes and the influence of potential consumers' preference have been mostly ignored. Besides, to the best of our knowledge, no research pays attention on the fact that some companies may snatch seeds to limit the profits of their opponents. Therefore, we propose a novel competition-based diversified-profit maximization (CDM) problem and its adaptive version, i.e., adaptive competition-based diversified-profit maximization (ACDM) problem. Different from prior works, these problems take seed's preference into consideration and use social welfare to reflect it. These two problems aim at selecting seeds and allocating them to marketers such that the sum of profit generated by consumers for a special entity after information dissemination and social welfare with respect to seed allocation reaches maximum. To address these two problems, we design an algorithm which combines the method of online allocation and the concept of Shapley value. Experimental results on three real-world data sets demonstrate the effectiveness of our proposed algorithm.

Multi-objective steel plate cutting optimization problem based on real number coding genetic algorithm.

The rectangular packing problem is an NP-complete combinatorial optimization problem. This problem occurs widely in social production scenarios, with steel plate cutting being one example. The cutting scheme for the rectangular packing problem needs to be improved because, without the globally optimal solution, there are many unnecessary edges in the steel cutting process. Based on a practical roll-fed disc shearing steel plate optimization problem, this paper explores a generalized packing method for rectangles of special dimensions and abstractly condenses complex quantitative relationships to establish a multi-objective mixed-integer nonlinear programming model. An innovative algorithm design based on a genetic algorithm is established to plan the cutting scheme in a high-speed and efficient way. The outcome is a utilization rate of up to 92.73% for raw materials and a significant reduction in labor, providing a guide for practical production and processing tasks. The advantages and disadvantages of the model and algorithm are discussed, and it is concluded that this rectangular packing method has strong universality and generalization ability, allowing rectangular packing tasks with large data volumes to be completed within a short time.

Multivariate genome-wide association study of leaf shape in a Populus deltoides and P. simonii F1 pedigree.

Leaf morphology exhibits tremendous diversity between and within species, and is likely related to adaptation to environmental factors. Most poplar species are of great economic and ecological values and their leaf morphology can be a good predictor for wood productivity and environment adaptation. It is important to understand the genetic mechanism behind variation in leaf shape. Although some initial efforts have been made to identify quantitative trait loci (QTLs) for poplar leaf traits, more effort needs to be expended to unravel the polygenic architecture of the complex traits of leaf shape. Here, we performed a genome-wide association analysis (GWAS) of poplar leaf shape traits in a randomized complete block design with clones from F1 hybrids of Populus deltoides and Populus simonii. A total of 35 SNPs were identified as significantly associated with the multiple traits of a moderate number of regular polar radii between the leaf centroid and its edge points, which could represent the leaf shape, based on a multivariate linear mixed model. In contrast, the univariate linear mixed model was applied as single leaf traits for GWAS, leading to genomic inflation; thus, no significant SNPs were detected for leaf length, measures of leaf width, leaf area, or the ratio of leaf length to leaf width under genomic control. Investigation of the candidate genes showed that most flanking regions of the significant leaf shape-associated SNPs harbored genes that were related to leaf growth and development and to the regulation of leaf morphology. The combined use of the traditional experimental design and the multivariate linear mixed model could greatly improve the power in GWAS because the multiple trait data from a large number of individuals with replicates of clones were incorporated into the statistical model. The results of this study will enhance the understanding of the genetic mechanism of leaf shape variation in Populus. In addition, a moderate number of regular leaf polar radii can largely represent the leaf shape and can be used for GWAS of such a complicated trait in Populus, instead of the higher-dimensional regular radius data that were previously considered to well represent leaf shape.

The complete chloroplast genome and characteristics analysis of Musa basjoo Siebold.

BACKGROUND: An ornamental plant often seen in gardens and farmhouses, Musa basjoo Siebold can also be used as Chinese herbal medicine. Its pseudostem and leaves are diuretic; its root can be decocted together with ginger and licorice to cure gonorrhea and diabetes; the decoct soup of its pseudostem can help relieve heat, and the decoct soup of its dried flower can treat cerebral hemorrhage. There have not been many chloroplast genome studies on M. basjoo Siebold. METHODS AND RESULTS: We characterized its complete chloroplast genome using Novaseq 6000 sequencing. This paper shows that the length of the chloroplast genome M. basjoo Siebold is 172,322 bp, with 36.45% GC content. M. basjoo Siebold includes a large single-copy region of 90,160 bp, a small single-copy region of 11,668 bp, and a pair of inverted repeats of 35,247 bp. Comparing the genomic structure and sequence data of closely related species, we have revealed the conserved gene order of the IR and LSC/SSC regions, which has provided a very inspiring discovery for future phylogenetic research. CONCLUSIONS: Overall, this study has constructed an evolutionary tree of the genus Musa species with the complete chloroplast genome sequence for the first time. As can be seen, there is no obvious multi-branching in the genus, and M. basjoo Siebold and Musa itinerans are the closest relatives.

[Metabonomics research on lung tissue of rats with acute exacerbation of chronic obstructive pulmonary disease treated with mineral Chinese medicine Chloriti Lapis].

To study the effect of mineral Chloriti Lapis on pulmonary metabolites and metabolic pathways in lung tissues of rats with acute exacerbation of chronic obstructive pulmonary disease(AECOPD). The AECOPD rat model of phlegm heat syndrome was replicated by the method of smoking combined with Klebsiella pneumoniae infection. Except for using UPLC-Q-TOF-MS analysis, SPSS 18.0, SIMCA 13.0 and other software were also used for statistical analysis. Through literature search and online database comparison, the differential metabolites were identified, and the possible metabolic pathways were analyzed. After 15 days of administration, PLS-DA analysis was carried out on lung tissue samples of rats in each group. The results showed that the metabolic profiles of lung tissues of rats in each group could be well separated, which indicated that Chloriti Lapis and aminophylline had significant intervention effect on the lung metabolic profile of rats with AECOPD. Moreover, the metabolic profile of Chloriti Lapis group was closer to that of control group, and the intervention effect was better than that of aminophylline group. As a result, 15 potential differential metabolites were identified: phytosphingosine, sphinganine, tetradecanoylcarnitine, L-palmitoylcarnitine, elaidic carnitine, lysoPC[18∶2(9Z,12Z)], lysoPC(16∶0), lysoPC[18∶1(9Z)], lysoPC(18∶0), stearic acid, lysoPC(15∶0), arachidonic acid, docosapentaenoic acid, linoleic acid and palmitic acid. Among them, Chloriti Lapis could significantly improve the levels of 10 differential metabolites of phytosphingosine, tetradecanoylcarnitine, L-palmitoylcarnitine, elaidic carnitine, lysoPC[18∶2(9Z,12Z)], lysoPC(16∶0), lysoPC[18∶1(9Z)], stearic acid, lysoPC(15∶0), and palmitic acid(P<0.05). The intervention effect of Chloriti Lapis group was better than that of aminophylline group. Analysis of metabolic pathways showed that there were 8 possible metabolic pathways that could be affected, and three of the most important metabolic pathways(pathway impact>0.1) were involved: linoleic acid metabolism, arachidonic acid metabolism, and sphingolipid metabolism. Chloriti Lapis had obvious intervention effects on lung tissue-related metabolites and metabolic pathways in rats with AECOPD, and the effect was better than that of aminophyllinne.

[Effects of mineral Chinese medicine Chloriti Lapis on contents of metal elements in plasma and lung tissue of acute exacerbation of chronic obstructive pulmonary disease(AECOPD) rats].

The effects of Chloriti Lapis on metal elements in plasma and lung tissue of acute exacerbation of chronic obstructive pulmonary disease( AECOPD) rats were studied. The rat AECOPD model with phlegm heat syndrome was established by smoking combined with Klebsiella pneumoniae infection. After the rats were treated by Chloriti Lapis,the contents of metal elements in plasma and lung tissue were determined by inductively coupled plasma-optical emission spectroscopy( ICP-OES) and inductively coupled plasma mass spectrometry( ICP-MS). The changes in the contents of metal elements were analyzed by SPSS 18. 0. Further,the correlations of differential metal elements( including Cu/Zn ratio) with differential metabolites in plasma,lung tissue and urine of AECOPD rats treated with Chloriti Lapis were analyzed. The results showed that Chloriti Lapis significantly up-regulated the contents of Fe,Al,Mn,Cu,Zn,Sn( P<0. 05),V,Co( P< 0. 01) and Cu/Zn ratio( P< 0. 05),and significantly down-regulated the contents of Ti( P< 0. 05)and Pb( P<0. 05) in the model rat plasma. It significantly increased the content of Be( P<0. 05) and decreased the contents of Mg,Ti and Al( P<0. 01) in model rat lung tissue. The element profiles of normal group,model group and Chloriti Lapis group can be well separated. Chloriti Lapis group and other groups were clustered into two categories. The taurine in plasma and phytosphingosine in lung tissue had the strongest correlations with differential metal elements. The Fe,Al,Mg,Be,Ti,V,Mn,Cu,Zn,Sn,and Co in Chloriti Lapis may directly or indirectly participate in the intervention of AECOPD rats. This group of metal elements may be the material basis of Chloriti Lapis acting on AECOPD rats,and reduce the Cu/Zn value in vivo. It was further confirmed that Chloriti Lapis could interfere with the metabolic pathways of taurine and hypotaurine in plasma and urine as well as the sphingolipid metabolism pathway in lung tissue of AECOPD rats. In addition,this study confirmed that long-term smoking can cause high-concentration Cd accumulation in the lung and damage the lung tissue.

Multivariate linear mixed model enhanced the power of identifying genome-wide association to poplar tree heights in a randomized complete block design.

With the advances in high-throughput sequencing technologies, it is not difficult to extract tens of thousands of single-nucleotide polymorphisms (SNPs) across many individuals in a fast and cheap way, making it possible to perform genome-wide association studies (GWAS) of quantitative traits in outbred forest trees. It is very valuable to apply traditional breeding experiments in GWAS for identifying genome variants associated with ecologically and economically important traits in Populus. Here, we reported a GWAS of tree height measured at multiple time points from a randomized complete block design (RCBD), which was established with clones from an F1 hybrid population of Populus deltoides and Populus simonii. A total of 22,670 SNPs across 172 clones in the RCBD were obtained with restriction site-associated DNA sequencing (RADseq) technology. The multivariate mixed linear model was applied by incorporating the pedigree relationship matrix of individuals to test the association of each SNP to the tree heights over 8 time points. Consequently, 41 SNPs were identified significantly associated with the tree height under the P-value threshold determined by Bonferroni correction at the significant level of 0.01. These SNPs were distributed on all but two chromosomes (Chr02 and Chr18) and explained the phenotypic variance ranged from 0.26% to 2.64%, amounting to 63.68% in total. Comparison with previous mapping studies for poplar height as well as the candidate genes of these detected SNPs were also investigated. We therefore showed that the application of multivariate linear mixed model to the longitudinal phenotypic data from the traditional breeding experimental design facilitated to identify far more genome-wide variants for tree height in poplar. The significant SNPs identified in this study would enhance understanding of molecular mechanism for growth traits and would accelerate marker-assisted breeding programs in Populus.

High-Quality SNP Linkage Maps Improved QTL Mapping and Genome Assembly in Populus.

With the advances in high-throughput sequencing technologies and the development of new software for extracting single nucleotide polymorphisms (SNPs) across a mapping population, it is possible to construct high-quality genetic maps with thousands of SNPs in outbred forest trees. Two parent-specific linkage maps were constructed with restriction site-associated DNA sequencing data from an F1 hybrid population derived from Populus deltoides and Populus simonii, and applied in QTL mapping and genome assembly. The female P. deltoides map contained 4018 SNPs, which were divided into 19 linkage groups under a wide range of LOD thresholds from 7 to 55. The male P. simonii map showed similar characteristics, consisting of 2097 SNPs, which also belonged to 19 linkage groups under LOD thresholds of 7 to 29. The SNP order of each linkage group was optimal among different ordering results from several available software. Moreover, the linkage maps allowed the detection of 39 QTLs underlying tree height and 47 for diameter at breast height. In addition, the linkage maps improved the anchoring of 689 contigs of P. simonii to chromosomes. The 2 parental genetic maps of Populus are of high quality, especially in terms of SNP data quality, the SNP order within linkage groups, and the perfect match between the number of linkage groups and the karyotype of Populus, as well as the excellent performances in QTL mapping and genome assembly. Both approaches for extracting and ordering SNPs could be applied to other species for constructing high-quality genetic maps.

The complete chloroplast genome and characteristics analysis of Callistemon rigidus R.Br.

Callistemon rigidus R.Br. one of the traditional Chinese medicinal plants, is acrid-flavored and mild-natured, with the prominent effects reducing swelling, resolving phlegm, and dispelling rheumatism. Clinically, it has been commonly used to treat cold, cough and asthma, pain and swelling from impact injuries, eczema, rheumatic arthralgia. The chloroplast genome study on Callistemon rigidus R.Br. is a few seen. This study demonstrates the data collected from the assembly and annotation of the chloroplast (cp) genome of Callistemon rigidus R.Br., followed by furthers comparative analysis with the cp genomes of closely related species. C. rigidus R.Br. showed a cp genome in the size of 158, 961 bp long with 36.78% GC content, among which a pair of inverted repeats (IRs) of 26, 671 bp separated a large single-copy (LSC) region of 87, 162 bp and a small single-copy (SSC) region of 18, 457 bp. Altogether 131 genes were hosted, including 37 transfer RNAs, 8 ribosomal RNAs, and 86 protein-coding genes. 284 simple sequence repeats (SSRs) were also marked out. A comparative analysis of the genome structure and the sequence data of closely related species unveiled the conserved gene order in the IR and LSC/SSC regions, a quite constructive finding for future phylogenetic research. Overall, this study providing C. rigidus R.Br. genomic resources could positively contribute to the evolutionary study and the phylogenetic reconstruction of Myrtaceae.

The Identification and Verification of Key Long Noncoding RNAs in Ischemic Stroke.

Stroke is a neurological disease with high rates of mortality and disability. The pathogenesis of stroke is acute focal injury of the central nervous system, leading to impaired neural function. Ischemic stroke accounts for the majority of cases. At present, the exact molecular mechanism of ischemic stroke remains unclear. Studies have shown that long noncoding RNAs (lncRNAs) have an important regulatory role in biological processes, participating in the regulation of transcription and affecting the processing and splicing of mRNAs. Abnormal lncRNA expression is associated with various diseases, including diseases of the nervous system. To identify and verify the key lncRNAs in ischemic stroke, we downloaded gene expression data from the National Center for Biotechnology Information Gene Expression Omnibus (NCBI GEO) and obtain differentially expressed lncRNAs, miRNAs, and mRNAs by bioinformatics analysis. Cytoscape was used to reconstruct a lncRNA-miRNA-mRNA network on the basis of the competitive endogenous RNA theory. We performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of the mRNAs regulated by lncRNAs in the lncRNA-miRNA-mRNA network. The resulting lncRNA-miRNA-mRNA network was composed of 91 lncRNA nodes, 70 mRNA nodes, 21 miRNA nodes, and 288 edges. GO analysis and KEGG pathway analysis have shown that 191 GO terms and 23 KEGG pathways were enriched. Finally, we found that four key lncRNAs were highly correlated with ischemic stroke and could be used as potential new targets for treatment.

gmRAD: an integrated SNP calling pipeline for genetic mapping with RADseq across a hybrid population.

Restriction site-associated DNA sequencing (RADseq) is a powerful technology that has been extensively applied in population genetics, phylogenetics and genetic mapping. Although many software packages are available for ecological and evolutionary studies, a few effective tools are available for extracting genotype data with RADseq for genetic mapping, a prerequisite for quantitative trait locus mapping, comparative genomics and genome scaffold assembly. Here, we present an integrated pipeline called gmRAD for generating single nucleotide polymorphism (SNP) genotypes from RADseq data, de novo, across a genetic mapping population derived by crossing two parents. As an analytical strategy, the software takes five steps to implement the whole algorithms, including clustering the first (forward) reads of each parent, building two parental references, generating parental SNP catalogs, calling SNP genotypes across all individuals and filtering the genotype data for genetic linkage mapping. All the steps can be completed with a simple command line, but they can be also performed optionally if prerequisite files are available. To validate its application, we also performed a real data analysis with RADseq data from an F1 hybrid population derived by crossing Populus deltoides and Populus simonii. The software gmRAD is freely available at https://github.com/tongchf/gmRAD.

De Novo Genome Assembly of Populus simonii Further Supports That Populus simonii and Populus trichocarpa Belong to Different Sections.

Populus simonii is an important tree in the genus Populus, widely distributed in the Northern Hemisphere and having a long cultivation history. Although this species has ecologically and economically important values, its genome sequence is currently not available, hindering the development of new varieties with wider adaptive and commercial traits. Here, we report a chromosome-level genome assembly of P. simonii using PacBio long-read sequencing data aided by Illumina paired-end reads and related genetic linkage maps. The assembly is 441.38 Mb in length and contain 686 contigs with a contig N50 of 1.94 Mb. With the linkage maps, 336 contigs were successfully anchored into 19 pseudochromosomes, accounting for 90.2% of the assembled genome size. Genomic integrity assessment showed that 1,347 (97.9%) of the 1,375 genes conserved among all embryophytes can be found in the P. simonii assembly. Genomic repeat analysis revealed that 41.47% of the P. simonii genome is composed of repetitive elements, of which 40.17% contained interspersed repeats. A total of 45,459 genes were predicted from the P. simonii genome sequence and 39,833 (87.6%) of the genes were annotated with one or more related functions. Phylogenetic analysis indicated that P. simonii and Populus trichocarpa should be placed in different sections, contrary to the previous classification according to morphology. The genome assembly not only provides an important genetic resource for the comparative and functional genomics of different Populus species, but also furnishes one of the closest reference sequences for identifying genomic variants in an F1 hybrid population derived by crossing P. simonii with other Populus species.

Identification of recombination events in outbred species with next-generation sequencing data.

BACKGROUND: Meiotic recombination events include crossovers and non-crossovers or gene conversions. Although the rate of crossovers is often used for genetic mapping, the gene conversion events are not well studied especially in outbred species, which could produce distorted markers and thus affect the precision of genetic maps. RESULTS: We proposed a strategy for identifying gene conversion events in Populus with the next-generation sequencing (NGS) data from the two parents and their progeny in an F1 hybrid population. The strategy first involved phasing the heterozygous SNPs of the parents to obtain the parental haplotype blocks by NGS analytical tools, permitting to identify the parental gene conversion events with progeny genotypes. By incorporating available genetic linkage maps, longer haplotype blocks each corresponding to a chromosome can be created, not only allowing to detect crossover events but also possibly to locate a crossover in a small region. Our analysis revealed that gene conversions are more abundant than crossovers in Populus, with a higher probability to generate distorted markers in the regions involved than in the other regions on genome. The analytical procedures were implemented with Perl scripts as a freely available package, findGCO at https://github.com/tongchf/findGCO . CONCLUSIONS: The novel strategy and the new developed Perl package permit to identify gene conversion events with the next-generation sequencing technology in a hybrid population of outbred species. The new method revealed that in a genetic mapping population some distorted genetic markers are possibly due to the gene conversion events.

[Mineral composition analysis and hemostatic effect of limonitum with different mineral genesis].

Models were established in mice with warfarin sodium method, and their bleeding time and hemostasis time were measured by tail cutting method and slide method respectively. Rats were administered for 15 consecutive days to measure their recalcification time, plasma viscosity, platelet adhesion rate, platelet aggregation rate and other blood indexes. As compared with the blank group, the bleeding time was prolonged in model groupn(P<0.05). As compared with the model group, the results showed that the positive vitamin K, the leaching type water decoction and the sediment type decoction could significantly shorten the bleeding time (P<0.01); positive vitamin K significantly (P<0.01) shortened clotting time, and the leaching type water decoction, the sediment type water decoction and the sediment type powder could also shorten the clotting time (P<0.05). As compared with blank group, low dose, medium dose of leaching type water decoction, medium dose of powder, high dose of sediment type decoction and low dose of drug residues could reduce plasma viscosity (P<0.05), and high dose of leaching powder and low dose of water decoction could significantly reduce (P<0.01) plasma viscosity. As compared with blank group, Limonitum leaching type decoction high dose group could significantly reduce the platelet adhesion rate (P<0.05), while sediment type water decoction could significantly increase the platelet adhesion rate (P<0.05); the high dose of leaching type water decoction, high dose of drug residues, low dose of leaching type powder and low dose of drug residues could decrease the platelet aggregation rate (P<0.05), while high dose of leaching type water decoction and high dose of the powder could increase the platelet aggregation rate (P<0.05). Analysis of mineral compositions was conducted by polarized light microscopy and X-ray diffraction (XRD). The results of the both methods showed that Limonitum mineral compositions contained goethite, quartz, and kaolinite, and sedimentary type also contained illite and albite. Sediment type of Limonitum showed better hemostatic effect, which may be related to the high content of goethite and illite.

[Association between chemical composition of essential oil with penetration enhancement effect and drug properties of traditional Chinese medicine].

The results of previous studies showed potential correlations between the penetration enhancement effect of essential oils and the drug properties of traditional Chinese medicine based on the data mining method. As chemical composition is the material basis of drug properties of traditional Chinese medicine, this article further analyzed the correlation between the chemical composition of essential oils and the drug properties. Firstly, essential oils were extracted by steam distillation, and then physicochemical parameters of essential oils, such as relative density and refractive index, were measured. The chemical components of 20 essential oils were analyzed by GC-MS, and divided into 12 categories according to skeleton features and functional groups. Finally, Logistic regression analysis was applied to reveal the correlations. The results proved that five flavors, four tastes and channel tropisms showed the correlation with chemical composition of essential oils (P<0.05). In conclusion, there were obvious correlations and regularity between the drug properties of traditional Chinese medicine and the chemical composition of essential oils.

[Association between penetration enhancement effect of essential oils and drug properties of traditional Chinese medicines by data mining method].

To study the association between penetration enhancement effect of essential oils and drug properties of traditional Chinese medicines. Through literature research, 34 kinds of essential oils with the penetration enhancement effect were collected. The methods of frequency analysis and variable crosstab were used for intuitive analysis and association analysis. The association between penetration enhancement effect of essential oils and drug properties (four natures, five flavors, channel tropism) were analyzed by a general linear model. According to the findings, the essential oils with penetration enhancement effect were all sourced from acrid traditional Chinese medicines, because their positive drug nature contributed to the enhancement of the penetration effect of essential oil; five flavors had little effect on penetration enhancement (P = 0.6982), but four natures and channel tropism showed significant effects (P = 0.011, 0.077). In conclusion, there were obvious association and regularity between penetration enhancement effect of essential oils and drug properties of traditional Chinese medicine.

Bicyclic guanidinium-catalyzed enantioselective phase-transfer alkylation: direct access to pyrroloindolines and furoindolines.

Highly enantioselective phase-transfer alkylation of 3-substituted-2-oxindoles with activated bromomethanes is disclosed with a broad substrate scope by using bicyclic guanidinium as a catalyst and a Lewis acid as the co-catalyst. The alkylation adducts are versatile intermediates to accomplish the syntheses of pyrroloindolines and furoindolines.

Organocatalytic asymmetric Michael addition of 5H-oxazol-4-ones to nitroolefins.

The first organocatalytic asymmetric Michael addition of 5H-oxazol-4-ones to nitroolefins has been developed. In the presence of easily prepared L-tert-leucine-derived tertiary amine/thiourea catalyst, the Michael addition of 5H-oxazol-4-ones to nitroolefins proceeded in an excellent diastereo- and enantioselective manner (up to 99% ee and >19:1 dr). The Michael adducts obtained are valuable precursors for the synthesis of chiral α-alkyl-α-hydroxy carboxylic acid derivatives, which represent a series of versatile building blocks in many biologically active compounds.