Highly Selective Nickel-Catalyzed Methyl-Carboxylation of Homopropargylic Alcohols for α-Alkylidene-γ-butyrolactones

A first practical Ni(0)-catalyzed highly stereoselective methyl-carboxylation of homopropargylic alcohols with ZnMe2 and CO2 for the efficient synthesis of α-alkylidene-γ-butyrolactones is described. The reaction may be applied to other alkynols

NaCl-Promoted Cobalt-Catalyzed Dioxygen-Mediated Methane Oxidation to Methylene Bis(trifluoroacetate) with a Dramatic Salt Effect

Although O2 is an ideal oxidant in the transformation of methane, very limited studies realize this process in homogeneous solvent systems with high efficiency under mild conditions. Herein, we present a NaCl-promoted cobalt-catalyzed O2-mediated methane oxidation with turnovers over 700 at 120 °C with a dramatic salt effect. The unexpected methylene bis(trifluoroacetate) can be produced with a selectivity up to 90%. This product is used in the reaction with TsNH2 and 1,2-diimine to efficiently form triazinane and imidazole salt, respectively. The Co-NaCl catalytic system is also applied in the oxidation of other hydrocarbons such as adamantane, 9,10-dihydrophenanthrene, 9,10-dihydroanthracene, and 9,10-dihydroacridine. Mechanistic studies indicate that NaCl can promote the decomposition of trifluoroacetic anhydride (TFAA) in the presence of Co(II), and a highly reactive fluorine radical might be formed to react with methane, generating a methyl radical, which will further react with O2 and then with trifluoroacetic anhydride to form methylene bis(trifluoroacetate)

Palladium-Catalyzed Cyclization Reactions of 2,3-Allenyl Amines with Propargylic Carbonates

A highly efficient and atom-economic route to synthesize 5-(1,3,4-alkatrien-2-yl)oxazolidin-2-ones via palladium-catalyzed cyclization reactions of 2,3-allenyl amines with propargylic carbonates was reported. The CO2 generated in situ from propargylic carbonates is incorporated into the oxazolidin-2-one unit with high efficiency, affording the products in 70–92% yields

Cyclic <i>Anti</i>-Azacarboxylation of 2‑Alkynylanilines with Carbon Dioxide

Direct anti-azacarboxylation of 2-alkynylanilines with CO2 mediated by ZnEt2 was observed to afford indole-3-carboxylic acids, a class of important compounds for the synthesis of many biologically active compounds, efficiently under 1 atm of CO2. The readily available nature of the different starting materials and tolerance of various functional groups provide vast opportunities for the efficient construction of diversified libraries for bioactive compounds listed in Figure . As an example, this methodology has been applied to the synthesis of Lotronex, a drug molecule used for the treatment of irritable bowel syndrome

Ligand-Promoted Bifunctional Cobalt-Catalyzed Carbonylation-Polymerization of Epoxides: One Step to Polyhydroxyalkanoates

Poly­(3-hydroxyalkanoates) (PHAs) are an important category of biodegradable plastics with properties similar to those of conventional ones. The development of a simple and efficient catalytic system for PHAs from the most abundant chemicals is economically important. Now we report an in situ generated bifunctional cobalt-catalyzed direct carbonylation-polymerization of epoxides in high efficiency in the presence of a diphosphine oxide ligand WenPhos oxide, which can be easily made from diphenyl sulfone in three steps with regular reagents. In addition, this ligand can promote the disproportionation of Co2(CO)8 to [Co­(CO)4]− and Co­(II) which is coordinated with phosphine oxide and sulfone oxide. Mechanistic studies indicate that this reaction is not from the ring-opening polymerization of in situ generated β-lactone. Instead, the phosphine oxide coordinated cobalt cation and [Co­(CO)4]− anion pair catalyzed direct carbonylation-polymerization of epoxide was proposed based on previous studies, some control experiments, and X-ray structures of the cobalt complexes

Carbometalation–Carboxylation of 2,3-Allenols with Carbon Dioxide: A Dramatic Effect of Halide Anion

The cyclic organometallic intermediates formed via CuCl-mediated highly regio- and stereoselective carbomagnesiation of 2,3-allenols with Grignard reagents may smoothly react with carbon dioxide to afford 2(5<i>H</i>)-furanones. A dramatic effect of the halide anion from the Grignard reagent (Br vs Cl) for CO₂ activation was observed. The reaction proceeded smoothly under mild conditions to afford the products in 58–93% yields

Zn-Mediated Scalable Synthesis of Trifluoromethylphosphines from Phosphine Chlorides and CF₃Br

Trifluoromethylphosphines represent a rare kind of phosphine with unique electronic withdrawing properties, which lead to some distinctive reactivities. The reported TFMPhos, products from nucleophilic or electrophilic trifluoromethylation of substrates, requiring one or more steps and prepared from phosphine chlorides, are very limited in structure diversity. Herein, we report a convenient and scalable (up to 100 mmol) recipe to synthesize diverse trifluoromethylphosphines via direct radical trifluoromethylation of phosphine chlorides with CF3Br in the presence of zinc powder

Pyridine <i>N</i>‑Oxide-Promoted Cobalt-Catalyzed Dioxygen-Mediated Methane Oxidation

The partial oxidation of methane with O2 is significant due to its potential of providing abundant chemical feedstock. Only a few examples realized this type of reaction in homogeneous solvent systems, most of which are in low efficiency. Herein, we present a pyridine N-oxide-promoted cobalt-catalyzed O2-mediated methane oxidation to produce methylene bis(trifluoroacetate) with productivity over 500 molester molmetal–1 h–1

Presentation_2_Isoleucine Enhances Plant Resistance Against Botrytis cinerea via Jasmonate Signaling Pathway.pptx

Amino acids are the building blocks of biomacromolecules in organisms, among which isoleucine (Ile) is the precursor of JA-Ile, an active molecule of phytohormone jasmonate (JA). JA is essential for diverse plant defense responses against biotic and abiotic stresses. Botrytis cinerea is a necrotrophic nutritional fungal pathogen that causes the second most severe plant fungal disease worldwide and infects more than 200 kinds of monocot and dicot plant species. In this study, we demonstrated that Ile application enhances plant resistance against B. cinerea in Arabidopsis, which is dependent on the JA receptor COI1 and the jasmonic acid-amido synthetase JAR1. The mutant lib with higher Ile content in leaves exhibits enhanced resistance to B. cinerea infection. Furthermore, we found that the exogenous Ile application moderately enhanced plant resistance to B. cinerea in various horticultural plant species, including lettuce, rose, and strawberry, suggesting a practical and effective strategy to control B. cinerea disease in agriculture. These results together showed that the increase of Ile could positively regulate the resistance of various plants to B. cinerea by enhancing JA signaling, which would offer potential applications for crop protection.</p

Presentation_3_Isoleucine Enhances Plant Resistance Against Botrytis cinerea via Jasmonate Signaling Pathway.pptx

Amino acids are the building blocks of biomacromolecules in organisms, among which isoleucine (Ile) is the precursor of JA-Ile, an active molecule of phytohormone jasmonate (JA). JA is essential for diverse plant defense responses against biotic and abiotic stresses. Botrytis cinerea is a necrotrophic nutritional fungal pathogen that causes the second most severe plant fungal disease worldwide and infects more than 200 kinds of monocot and dicot plant species. In this study, we demonstrated that Ile application enhances plant resistance against B. cinerea in Arabidopsis, which is dependent on the JA receptor COI1 and the jasmonic acid-amido synthetase JAR1. The mutant lib with higher Ile content in leaves exhibits enhanced resistance to B. cinerea infection. Furthermore, we found that the exogenous Ile application moderately enhanced plant resistance to B. cinerea in various horticultural plant species, including lettuce, rose, and strawberry, suggesting a practical and effective strategy to control B. cinerea disease in agriculture. These results together showed that the increase of Ile could positively regulate the resistance of various plants to B. cinerea by enhancing JA signaling, which would offer potential applications for crop protection.</p