Palladium-Catalyzed Direct C-3 Alkynylation of Indolizines with (2,2-Dibromovinyl)arenes

<div><p></p><p>The direct C-3 alkynylation of indolizines with (2,2-dibromovinyl)arenes in the presence of palladium catalyst has been developed. This novel protocol showed wide substrate scope with respect to both indolizines and dibromoalkenes. Also this method was characterized with high efficiency and good functional group tolerance.</p> </div

Copper-Catalyzed Reaction of Ketenimine and in Situ Generated Immonium Ion: Access to α<i>,</i>β‑Unsaturated Amidines

A Cu-catalyzed three-component reaction of alkyne, azides (sulfonyl or phosphoryl azides), and <i><i>N</i></i>,<i><i>N</i></i>-dialkyloxyformamide dialkyl acetal via electrophilic addition of immonium ion to copper ketenimine is reported. This new protocol for the preparation of α,β-unsaturated amidine derivatives appears to offer high yield, mild conditions, and wide substrate scope. The reaction might involve the processes of copper ketenimine intermediate formation, electrophilic addition, and isomerization

Palladium(II)-Catalyzed <i>ortho</i>-Olefination of Arenes Applying Sulfoxides as Remote Directing Groups

A novel palladium-catalyzed <i>ortho</i>-C­(sp²)–H olefination protocol has been developed by the use of sulfoxide as the directing group. Importantly, relatively remote coordination can be accessed to achieve the <i>ortho</i> olefination of benzyl, 2-arylethyl, and 3-arylpropenyl sulfoxide substrates, and the olefinated sulfoxide can be easily transformed to other functionalities

Palladium(II)-Catalyzed <i>ortho</i>-Olefination of Arenes Applying Sulfoxides as Remote Directing Groups

A novel palladium-catalyzed <i>ortho</i>-C­(sp²)–H olefination protocol has been developed by the use of sulfoxide as the directing group. Importantly, relatively remote coordination can be accessed to achieve the <i>ortho</i> olefination of benzyl, 2-arylethyl, and 3-arylpropenyl sulfoxide substrates, and the olefinated sulfoxide can be easily transformed to other functionalities

Palladium(II)-Catalyzed <i>ortho</i>-Olefination of Arenes Applying Sulfoxides as Remote Directing Groups

A novel palladium-catalyzed <i>ortho</i>-C­(sp²)–H olefination protocol has been developed by the use of sulfoxide as the directing group. Importantly, relatively remote coordination can be accessed to achieve the <i>ortho</i> olefination of benzyl, 2-arylethyl, and 3-arylpropenyl sulfoxide substrates, and the olefinated sulfoxide can be easily transformed to other functionalities

Palladium(II)-Catalyzed <i>ortho</i>-Olefination of Arenes Applying Sulfoxides as Remote Directing Groups

A novel palladium-catalyzed <i>ortho</i>-C­(sp²)–H olefination protocol has been developed by the use of sulfoxide as the directing group. Importantly, relatively remote coordination can be accessed to achieve the <i>ortho</i> olefination of benzyl, 2-arylethyl, and 3-arylpropenyl sulfoxide substrates, and the olefinated sulfoxide can be easily transformed to other functionalities

Synthesis of 2-(phenoxymethyl)oxirane derivatives through unexpected rearrangement of oxiran-2-ylmethyl benzenesulfonates

<p>The synthesis of 2-(phenoxymethyl)oxirane derivatives from oxiran-2-ylmethyl benzenesulfonates was developed through a base promoted rearrangement. A new C-O bond was formed along with the unexpected cleavage of C-S bond via this process. This unusual reaction was characterized with mild reaction conditions, high efficiency, and excellent functional group tolerance. A plausible reaction mechanism was proposed on the basis of experimental results and control experiments.</p

Comparative Transcriptome Analysis of Two <i>Ipomoea aquatica</i> Forsk. Cultivars Targeted To Explore Possible Mechanism of Genotype-Dependent Accumulation of Cadmium

A low-shoot-Cd (QLQ) and a high-shoot-Cd cultivar (T308) of water spinach (<i>Ipomoea aquatica</i> Forsk.) were used to investigate molecular mechanism of the genotype difference in cadmium (Cd) accumulation. RNA-Seq under 9 and 72 h cadmium exposures (5 mg L^–1) were undertaken to explore Cd induced genotype differences in molecular processes. In total, 253 747 540 clean reads were assembled into 57 524 unigenes. Among them, 6136 and 10 064 unigenes were differentially expressed in QLQ and T308, respectively. Cell wall biosynthesis genes, such as <i>GAUT</i> and <i>laccase</i>, and three Cd efflux genes (<i>Nramp5</i>, <i>MATE9</i>, and <i>YSL7</i>) had higher expression levels in QLQ, while the genes in sulfur and glutathione metabolism pathway, e.g., sulfate transporter and cysteine synthase, showed higher expression levels in T308. These findings would be useful for further understanding of the mechanisms related to genotype-dependent Cd accumulation and developing the molecular assisted screening and breeding of low-shoot-Cd cultivars for water spinach

Comparative Transcriptome Analysis between Low- and High-Cadmium-Accumulating Genotypes of Pakchoi (<i>Brassica chinensis</i> L.) in Response to Cadmium Stress

To reduce cadmium (Cd) pollution of food chains, screening and breeding of low-Cd-accumulating cultivars are the focus of much study. Two previously identified genotypes, a low-Cd-accumulating genotype (LAJK) and a high-Cd-accumulating genotype (HAJS) of pakchoi (Brassica chinesis L.), were stressed by Cd (12.5 μM) for 0 h (T0), 3 h (T3) and 24 h (T24). By comparative transcriptome analysis for root tissue, 3005 and 4343 differentially expressed genes (DEGs) were identified in LAJK at T3 (vs T0) and T24 (vs T3), respectively, whereas 8677 and 5081 DEGs were detected in HAJS. Gene expression pattern analysis suggested a delay of Cd responded transcriptional changes in LAJK compared to HAJS. DEG functional enrichments proposed genotype-specific biological processes coped with Cd stress. Cell wall biosynthesis and glutathione (GSH) metabolism were found to involve in Cd resistance in HAJS, whereas DNA repair and abscisic acid (ABA) signal transduction pathways played important roles in LAJK. Furthermore, the genes participating in Cd efflux such as <i>PDR8</i> were overexpressed in LAJK, whereas those responsible for Cd transport such as <i>YSL1</i> were more enhanced in HAJS, exhibiting different Cd transport processes between two genotypes. These novel findings should be useful for molecular assisted screening and breeding of low-Cd-accumulating genotypes for pakchoi

Comparative Transcriptome Analysis between Low- and High-Cadmium-Accumulating Genotypes of Pakchoi (<i>Brassica chinensis</i> L.) in Response to Cadmium Stress

To reduce cadmium (Cd) pollution of food chains, screening and breeding of low-Cd-accumulating cultivars are the focus of much study. Two previously identified genotypes, a low-Cd-accumulating genotype (LAJK) and a high-Cd-accumulating genotype (HAJS) of pakchoi (Brassica chinesis L.), were stressed by Cd (12.5 μM) for 0 h (T0), 3 h (T3) and 24 h (T24). By comparative transcriptome analysis for root tissue, 3005 and 4343 differentially expressed genes (DEGs) were identified in LAJK at T3 (vs T0) and T24 (vs T3), respectively, whereas 8677 and 5081 DEGs were detected in HAJS. Gene expression pattern analysis suggested a delay of Cd responded transcriptional changes in LAJK compared to HAJS. DEG functional enrichments proposed genotype-specific biological processes coped with Cd stress. Cell wall biosynthesis and glutathione (GSH) metabolism were found to involve in Cd resistance in HAJS, whereas DNA repair and abscisic acid (ABA) signal transduction pathways played important roles in LAJK. Furthermore, the genes participating in Cd efflux such as <i>PDR8</i> were overexpressed in LAJK, whereas those responsible for Cd transport such as <i>YSL1</i> were more enhanced in HAJS, exhibiting different Cd transport processes between two genotypes. These novel findings should be useful for molecular assisted screening and breeding of low-Cd-accumulating genotypes for pakchoi