Cucumber is an economically important crop as well as a model system for sex determination studies and plant vascular biology. Here we report the draft genome sequence of Cucumis sativus var. sativus L., assembled using a novel combination of traditional Sanger and next-generation Illumina GA sequencing technologies to obtain 72.2-fold genome coverage. The absence of recent whole-genome duplication, along with the presence of few tandem duplications, explains the small number of genes in the cucumber. Our study establishes that five of the cucumber's seven chromosomes arose from fusions of ten ancestral chromosomes after divergence from Cucumis melo. The sequenced cucumber genome affords insight into traits such as its sex expression, disease resistance, biosynthesis of cucurbitacin and 'fresh green' odor. We also identify 686 gene clusters related to phloem function. The cucumber genome provides a valuable resource for developing elite cultivars and for studying the evolution and function of the plant vascular system.

Using next-generation sequencing technology alone, we have successfully generated and assembled a draft sequence of the giant panda genome. The assembled contigs (2.25 gigabases (Gb)) cover approximately 94% of the whole genome, and the remaining gaps (0.05 Gb) seem to contain carnivore-specific repeats and tandem repeats. Comparisons with the dog and human showed that the panda genome has a lower divergence rate. The assessment of panda genes potentially underlying some of its unique traits indicated that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition. We also identified more than 2.7 million heterozygous single nucleotide polymorphisms in the diploid genome. Our data and analyses provide a foundation for promoting mammalian genetic research, and demonstrate the feasibility for using next-generation sequencing technologies for accurate, cost-effective and rapid de novo assembly of large eukaryotic genomes.

Here we present the first diploid genome sequence of an Asian individual. The genome was sequenced to 36-fold average coverage using massively parallel sequencing technology. We aligned the short reads onto the NCBI human reference genome to 99.97% coverage, and guided by the reference genome, we used uniquely mapped reads to assemble a high-quality consensus sequence for 92% of the Asian individual's genome. We identified approximately 3 million single-nucleotide polymorphisms (SNPs) inside this region, of which 13.6% were not in the dbSNP database. Genotyping analysis showed that SNP identification had high accuracy and consistency, indicating the high sequence quality of this assembly. We also carried out heterozygote phasing and haplotype prediction against HapMap CHB and JPT haplotypes (Chinese and Japanese, respectively), sequence comparison with the two available individual genomes (J. D. Watson and J. C. Venter), and structural variation identification. These variations were considered for their potential biological impact. Our sequence data and analyses demonstrate the potential usefulness of next-generation sequencing technologies for personal genomics.

The first Ir-catalyzed intramolecular asymmetric allylic dearomatization reaction of pyridines, pyrazines, quinolines, and isoquinolines has been developed. Enabled by in situ formed chiral Ir-catalyst, the dearomatized products were isolated in high levels of yield (up to 99% yield) and enantioselectivity (up to 99% ee). It is worth noting that the Me-THQphos ligand is much more efficient than other tested ligands for the dearomatization of pyrazines and certain quinolines. Mechanistic studies of the dearomatization reaction were carried out, and the results suggest the feasibility of an alternative process which features the formation of a quinolinium as the key intermediate. The mechanistic findings render this reaction a yet unknown type in the chemistry of Reissert-type reactions. In addition, the utility of this method was showcased by a large-scale reaction and formal synthesis of (+)-gephyrotoxin.

The yields have not been optimized.General Procedure 1 (GP-1): Preparation of the electrophile. 2 An oven-dried 100 mL round-bottom flask was charged with a magnetic stir bar and either ZnCl2 or ZnBr2 (0.050 equiv), and then it was sealed with a rubber septum cap. The flask was placed under a nitrogen atmosphere by evacuating and backfilling the flask (three cycles), followed by the addition of DCM and the acyl bromide (1.2 equiv). The resulting solution was cooled to -10 °C, and the mixture was stirred for 10 min. At this temperature, the aldehyde (1.0 equiv) was added via syringe pump over 30 min, and the resulting mixture was stirred for 2 h. Then, the reaction mixture was filtered through a short column of neutral aluminium oxide, with a DCM washing. The filtrate was concentrated under reduced pressure. The residue was either purified by vacuum distillation to afford the pure product, or used directly after the determination of its purity by 1 H NMR (CH2Br2 as the internal standard).1-Bromoethyl benzoate. The title compound was synthesized according to GP-1 from ZnCl2 (544 mg, 4.0 mmol), BzBr (11.3 mL, 96.0 mmol), acetaldehyde (4.5 mL, 80 mmol), and DCM (10 mL). The product was purified by vacuum distillation (b.p. = 75-79 °C, 1.2 Torr). 9.6 g (42.1 mmol, 53% yield). Colorless oil. 1 H NMR (400 MHz, CDCl3) δ 8.12 -8.04 (m, 2H), 7.65 -7.56 (m, 1H), 7.52 -7.42 (m, 2H), 6.97 (q, J = 5.9 Hz, 1H), 2.14 (d, J = 5.9 Hz, 3H). cm -1 .1-Bromopropyl benzoate. The title compound was synthesized according to GP-1 from ZnCl2 (870 mg, 6.4 mmol), BzBr (18.0 mL, 154 mmol), propionaldehyde (9.2 mL, 128 mmol), and DCM (20 mL). The product was purified by vacuum distillation (b.p. = 88-90 °C, 0.5 Torr). 22.4 g (92.6 mmol, 72% yield). Colorless oil. ZnCl 2 or ZnBr 2 DCM, -10 °C R O Br Br R 1 O R 1 O H R O S-4 1 H NMR (500 MHz, CDCl3) δ 8.10 -8.05 (m, 2H), 7.65 -7.58 (m, 1H), 7.50 -7.43 (m, 2H), 6.85 (t, J = 5.7 Hz, 1H), 2.36 -2.23 (m, 2H), 1.15 (t, J = 7.3 Hz, 3H). , 961, 908, 716 cm -1 . 1-Bromopentyl benzoate. The title compound was synthesized according to GP-1 from ZnCl2 (544 mg, 4.0 mmol), BzBr (11.3 mL, 96.0 mmol), valeraldehyde (8.5 mL, 80 mmol), and DCM (10 mL). The product was purified by vacuum distillation (b.p. = 103-108 °C, 0.7 Torr). 8.4 g (31.1 mmol, 39% yield). Yellow oil. 1 H NMR (400 MHz, CDCl3) δ 8.10 -8.04 (m, 2H), 7.66 -7.57 (m, 1H), 7.52 -7.44 (m, 2H), 6.89 (t, J = 5.9 Hz, 1H), 2.37 -2.21 (m, 2H), 1.61 -1.49 (m, 2H), 1.48 -1.35 (m, 2H), 0.95 (t, J = 7.3 Hz, 3H). cm -1 .1-Bromo-3-methylbutyl benzoate. The title compound was synthesized according to GP-1 from ZnBr2 (888 mg, 4.0 mmol), BzBr (11.3 mL, 96.0 mmol), isovaleraldehyde (8.6 mL, 80 mmol), and DCM (10 mL). The product was purified by vacuum distillation (b.p. = 95-98 °C, 0.7 Torr). 14.3 g (53.0 mmol, 66% yield). Colorless oil. 1 H NMR (400 MHz, CDCl3) δ 8.12 -8.04 (m, 2H), 7.65 -7.57 (m, 1H), 7.53 -7.42 (m, 2H), 6.95 (dd, J = 7.6, 5.6 Hz, 1H), 2.28 (ddd, J = 14.2, 7.6, 6.6 Hz, 1H), 2.16 (ddd, J = 14.3, 7.3, 5.6 Hz, 1H), 1.99 -1.86 (m, 1H), 0.99 (d, J = ...

The development of efficient methods, particularly catalytic and enantioselective processes, for the construction of all-carbon quaternary stereocentres is an important (and difficult) challenge in organic synthesis, due to the occurrence of this motif in a range of bioactive molecules. One conceptually straightforward and potentially versatile approach is the catalytic enantioconvergent substitution reaction of a readily available racemic tertiary alkyl electrophile by an organometallic nucleophile; however, examples of such processes are rare. In this report, we demonstrate that a nickel-based chiral catalyst achieves enantioconvergent couplings of a variety of tertiary electrophiles (cyclic and acyclic α -halocarbonyl compounds) with alkenylmetal nucleophiles to form quaternary stereocentres with good yield and enantioselectivity under mild conditions in the presence of a range of functional groups. These couplings, which likely proceed via a radical pathway, provide access to an array of useful families of organic compounds, including intermediates in the total synthesis of two natural products, (−)-eburnamonine and madindoline A.

The YH database is a server that allows the user to easily browse and download data from the first Asian diploid genome. The aim of this platform is to facilitate the study of this Asian genome and to enable improved organization and presentation large-scale personal genome data. Powered by GBrowse, we illustrate here the genome sequences, SNPs, and sequencing reads in the MapView. The relationships between phenotype and genotype can be searched by location, dbSNP ID, HGMD ID, gene symbol and disease name. A BLAST web service is also provided for the purpose of aligning query sequence against YH genome consensus. The YH database is currently one of the three personal genome database, organizing the original data and analysis results in a user-friendly interface, which is an endeavor to achieve fundamental goals for establishing personal medicine. The database is available at http://yh.genomics.org.cn.

The first iridium-catalyzed intramolecular asymmetric allylic dearomatization reaction of pyridines and pyrazines has been realized. 2,3-Dihydroindolizine and 6,7-dihydropyrrolo[1,2-a]pyrazine derivatives were obtained with excellent yields and enantioselectivity. This methodology features dearomatization by direct N-allylic alkylation of pyridines or pyrazines under mild reaction conditions.