A trans-Selective Hydroboration of Internal Alkynes

Violate the rule: The reigning stereochemical principle of hydroboration is the suprafacial delivery of hydrogen and boron to the same π-face of a given starting material. This fundamental rule of cis addition is now easily broken for internal alkynes with the help of [Cp*Ru(MeCN)3]PF6 (Cp*=η5-C5Me5) as the catalyst. The resulting trans-selective hydroboration opens a practical new entry into E-configured alkenylboron derivatives

A dual input single output non-isolated DC-DC converter for multiple sources electric vehicle applications

There is a need to design DC-DC converters capable of handling high voltages and that employ single-stage conversion to integrate renewable energy resources, such as solar photovoltaic cells and fuel cells, for electric vehicle applications. This paper elucidates the design and analysis of a dual input single output non-isolated Cuk-derived converter with a high step-up ratio. The proposed converter can effectively handle two different energy resources that have different electrical characteristics. It makes use of one common inductor between the dual input port, which reduces the passive components and the circuit volume required. The maximum efficiency that can be achieved by this converter is 95.72%, with two main switches and one diode in the circuit. This study involved a detailed analysis of the proposed converter in continuous current operation mode. A continuous current with reduced ripple in the output improves a fuel cell’s operating life-span. The efficacy of the proposed converter is verified through simulation and validated by constructing a 200 W, real-time, scaled-down prototype model

A Functional-Group-Tolerant Catalytic trans Hydrogenation of Alkynes

Against the rules: During the hundred years following Sabatier's groundbreaking work on catalytic hydrogenation, syn delivery of the H atoms to the π system of a substrate remained the governing stereochemical rule. An exception has now be found with the use of cationic [Cp*Ru] templates, which accounts for the first practical, functional-group-tolerant, broadly applicable and highly E-selective semihydrogenation method for alkynes (see scheme)

Efficacy of certain botanicals against root-lesion nematode, Pratylenchus coffeae in banana.

The root-lesion nematode, Pratylenchus coffede causes extensive root damage to banana which results in serious economic losses. Because nematicides are very expensive, control strategies are nowadays directed towards the use of natura1 products. Manuring with green and dry plant parts have been practised as a method for the control of plant parasitic nematodes (Osman et al., 1989). Leaf extracts of Glyricidia maculata, Ricinus communis, Crotalaria juncea, Glycosmis pentaphylla, Azadirachta indica, Kalanchoe pinnata, Piper betle and Moringa oleifera have been reported to be lethal to Radopholus similis (Tasy and Koshy, 1992). Intercropping of banana with C. juncea was found to reduce R. similis with irnproved growth and yield of banana in India (Charles and Venkitesan, 1993). Significant yield increases and reduction in P coffeae populations were also recorded in banana plants treated with 50 per cent of N applied by neem cake (Sundararaju and Kumar, 2000). The present paper reports the result of a field experiment undertaken to test the nematicidal efficacy of leaves belonging to ten botanicals.Dry and fresh leaves of ten locally available botanicals were tested against the root-lesion nematode, Pratylenchus coffeae in banana cvs Nendran and Rasthali under field conditions. All the botanicals were effective in reducing the nematode population and subsequently increased the plant growth characters and yield compared to untreated control. Among the different botanicals tried, application of Azadirachta indica, Calotropis procera, Datura stramonium, Crotolaria juncea and Vitex negundo were found to be superior and effective in reducing the nematode population and increasing the yield significantly

sp3 C-H bond activation with ruthenium(II) catalysts and C(3)-alkylation of cyclic amines.

International audienceA selective C(3)-alkylation via activation/functionalization of sp(3) C-H bond of saturated cyclic amines was promoted by (arene)ruthenium(II) complexes featuring a bidentate phosphino-sulfonate ligand upon reaction with aldehydes. This highly regioselective sustainable transformation takes place via initial dehydrogenation of cyclic amines and hydrogen autotransfer processes

Efficient ruthenium-catalyzed synthesis of [3]dendralenes from 1,3-dienic allylic carbonates

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Isoquinoline derivatives via stepwise regioselective sp2 and sp3C-H bond functionalization

International audienceEfficient and practically attractive stepwise ruthenium- and palladium-catalyzed regioselective C−H bond functionalizations were achieved to produce 4- substituted tetrahydroisoquinoline derivatives featuring various heteroaromatic substructures in moderate to good yields. Both ruthenium- and palladium-based catalytic processes generated nontoxic and easily separable side products

Ruthenium-catalyzed cascade N- and C(3)-dialkylation of cyclic amines with alcohols involving hydrogen autotransfer processes

International audienceAn unprecented N- and C(3)-dialkylation of unactivated amines by a cascade reaction via borrowing hydrogen methodology using new (arene)ruthenium(II) complexes featuring phosphinosulfonate ligands is described. This reaction is highly regioselective and produces water as the only side product