prakash basnet - Academia.edu (original) (raw)
Papers by prakash basnet
Frontiers in Plant Science
The plant hormone gibberellic acid (GA) is important for plant growth and productivity. Actin-rel... more The plant hormone gibberellic acid (GA) is important for plant growth and productivity. Actin-related proteins (ARPs) also play central roles in plant growth, including cell elongation and development. However, the relationships between ARPs and GA signaling and biosynthesis are not fully understood. Here, we isolated OsGASD, encoding an ARP subunit from rice (Oryza sativa), using the Ac/Ds knockout system. The osgasd knockout (Ko) mutation reduced GA3 content in shoots as well as plant growth and height. However, GA application restored the plant height of the osgasd Ko mutant to a height similar to that of the wild type (WT). Rice plants overexpressing OsGASD (Ox) showed increased plant height and grain yield compared to the WT. Transcriptome analysis of flag leaves of OsGASD Ox and osgasd Ko plants revealed that OsGASD regulates cell development and the expression of elongation-related genes. These observations suggest that OsGASD is involved in maintaining GA homeostasis to regu...
Agronomy
Short crop height is the preferred breeding trait since there is a positive correlation between l... more Short crop height is the preferred breeding trait since there is a positive correlation between lodging resistance and a crop yield increase. Alternative splicing can alter transcriptome diversity and contribute to plant adaptation to environmental stress. We characterized the transcriptomes obtained from dwarf and normal soybean lines derived from a cross of Glycine max var. Peking (G. max) and G. soja var. IT182936 in an F7 RIL population to study the differences between the isoforms. Full-length mRNA derived from leaf tissues was sequenced using the PacBio RSII platform, generating 904,474 circular consensus sequence (CCS) reads. Using the Structural and Quality Annotation of Novel Transcript Isoforms (SQANTI) process, 42,582 and 44,762 high-quality isoforms, and 91 and 179 polished low-quality isoforms were obtained in dwarf and normal cells, respectively. As a result, 832 and 36,772 nonredundant transcripts were generated. Approximately 30% of the identified genes were estimate...
Frontiers in Genetics, 2022
In cultivated plants, shoot morphology is an important factor that influences crop economic value... more In cultivated plants, shoot morphology is an important factor that influences crop economic value. However, the effects of gene expression patterns on shoot morphology are not clearly understood. In this study, the molecular mechanism behind shoot morphology (including leaf, stem, and node) was analyzed using RNA sequencing to compare weedy (creeper) and cultivar (stand) growth types obtained in F7 derived from a cross of wild and cultivated soybeans. A total of 12,513 (in leaves), 14,255 (in stems), and 11,850 (in nodes) differentially expressed genes were identified among weedy and cultivar soybeans. Comparative transcriptome and expression analyses revealed 22 phytohormone-responsive genes. We found that GIBBERELLIN 2-OXIDASE 8 (GA2ox), SPINDLY (SPY), FERONIA (FER), AUXIN RESPONSE FACTOR 8 (ARF8), CYTOKININ DEHYDROGENASE-1 (CKX1), and ARABIDOPSIS HISTIDINE KINASE-3 (AHK3), which are crucial phytohormone response genes, were mainly regulated in the shoot of weedy and cultivar type...
Plant Signaling & Behavior, 2021
ABSTRACT Selaginella tamariscina is a lycophyta species that survives under extremely dry conditi... more ABSTRACT Selaginella tamariscina is a lycophyta species that survives under extremely dry conditions via the mechanism of resurrection. This phenomenon involves the regulation of numerous genes that play vital roles in desiccation tolerance and subsequent rehydration. To identify resurrection-related genes, we analyzed the transcriptome between dehydration conditions and rehydration conditions of S. tamariscina. The de novo assembly generated 124,417 transcripts with an average size of 1,000 bp and 87,754 unigenes. Among these genes, 1,267 genes and 634 genes were up and down regulated by rehydration compared to dehydration. To understand gene function, we annotated Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The unigenes encoding early light-inducible protein (ELIP) were down-regulated, whereas pentatricopeptide repeat-containing protein (PPR), late embryogenesis abundant proteins (LEA), sucrose nonfermenting protein (SNF), trehalose phosphate phosphatase (TPP), trehalose phosphate synthase (TPS), and ABC transporter G family (ABCG) were significantly up-regulated in response to rehydration conditions by differentially expressed genes (DEGs) analysis. Several studies provide evidence that these genes play a role in stress environment. The ELIP and PPR genes are involved in chloroplast protection during dehydration and rehydration. LEA, SNF, and trehalose genes are known to be oxidant scavengers that protect the cell structure from the deleterious effect of drought. TPP and TPS genes were found in the starch and sucrose metabolism pathways, which are essential sugar-signaling metabolites regulating plant metabolism and other biological processes. ABC-G gene interacts with abscisic acid (ABA) phytohormone in the stomata opening during stress conditions. Our findings provide valuable information and candidate resurrection genes for future functional analysis aimed at improving the drought tolerance of crop plants.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
The study found that community livelihood has dependent on the traditional subsistence agricultur... more The study found that community livelihood has dependent on the traditional subsistence agriculture and use of forest resource. Dependency on the natural resource was found to be high and use of alternative source of energy is low which had adverse impact on the forest.Bufferzone programme appears to not to decrease need pressure. Distributions of Bufferzone forest resources were found to be unequal among the households.Information on 70 household was gathered to tie up with vegetation study. For the tree species 12 sample plots, 24 plots for shrubs and herbs were studied. Of these 2 tree species, 22 shrubs and 20 herbs were studied. Density, species diversity, IVI, basal area, volume, biomass and annual yield of plant were low. Regeneration of plant species was low because anthropogenic pressure on forest of Bufferzone found to be high.
Indian Journal of Genetics and Plant Breeding, 2020
Soybean cyst nematode (SCN) is one of the most damaging pest of soybean. Discovery and characteri... more Soybean cyst nematode (SCN) is one of the most damaging pest of soybean. Discovery and characterization of the genes involved in SCN resistance are important in soybean breeding. Soluble NSF attachment protein (SNAP) genes are related to SCN resistance in soybean. SNAP genes include five gene families, and 2 haplotypes of exons 6 and 9 of SNAP18 are considered resistant to the SCN. In present study the haplotypes of GmSNAP18 were surveyed and chacterized in a total of 60 diverse soybean genotypes including Korean cultivars, landraces, and wild-types. The target region of exons 6 and 9 in GmSNAP18 region was amplified and sequenced to examine nucleotide variation. Characterization of 5 haplotypes identified in present study for the GmSNAP18 gene revealed two haplotypes as resistant, 1 as susceptible and two as novel. A total of twelve genotypes showed resistant haplotypes, and 45 cultivars were found susceptible. Interestingly, the two novel haplotypes were present in 3 soybean lines...
Organic Letters, 2020
We describe herein a Cu(OTf) 2 catalyzed oxidative arylation of a tertiary carbon-containing subs... more We describe herein a Cu(OTf) 2 catalyzed oxidative arylation of a tertiary carbon-containing substrates including aryl malononitriles, 3-aryl benzofuran-2-ones, and 3-aryl oxindoles. In some cases, the nitrile groups of the aryl malononitriles undergo further reactions leading to lactones or imines. These reaction conditions are applicable for a range of arenes, including phenols, anilines, anisoles and heteroarenes. Mechanistic studies support the formation of a cationic intermediate via a two-electron oxidation.
ACS Catalysis, 2019
All the reactions were set up inside a nitrogen-filled glovebox and all the chemicals were handle... more All the reactions were set up inside a nitrogen-filled glovebox and all the chemicals were handled under nitrogen atmosphere unless stated otherwise. All the glassware including the 4-dram, 1-dram borosilicate (Kimble-Chase) vials, and pressure vessels were properly dried in an oven before use. Bulk solvents were obtained from EMD, anhydrous solvents (DMF, DMA, DMSO, NMP, dioxane, toluene, MeCN) were obtained from Sigma-Aldrich and were used directly without further purification. Deuterated solvents were purchased from Sigma-Aldrich. NiCl2 was purchased from Alfa-Aesar. 1 H, 13 C and 19 F NMR spectra were recorded on a Bruker instrument (300, 75 and 282 MHz respectively) and internally referenced to the residual solvent signals of CDCl3 for 1 H and 13 C NMR, and C6F6 for 19 F NMR at 7.26 ppm, 77.16 ppm and −164.9 ppm respectively. The chemical shifts of NMR and the coupling constants (J) for 1 H, 13 C and 19 F NMR are reported in δ parts per millions (ppm) and in Hertz, respectively. The following conventions are used for multiplicities: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; dd, doublet of doublet; s, br, singlet broad; ddd, doublet of doublet of doublet. High resolution mass spectra of new compounds were recorded at the mass spectrometry facility, Department of Chemistry and Chemical Biology, University of New Mexico (UNM). All NMR spectra were collected at Department of Chemistry and Chemical Biology, UNM. The X-ray data were measured on a Bruker Kappa APEXII Duo system equipped with a fine-focus sealed tube (Mo Kα, λ = 0.71073 Å) and a graphite monochromator at the X-ray facility at the University of Virginia. Infrared (IR) spectra were recorded on Bruker Alpha-P ATR-IR at UNM and νmax is reported in cm-1 at UNM. 2. Experimental Section 2.1. Preparation of Substrates ethyl 2-cyanopent-4-enoate was prepared following literature procedure. 1
This paper discusses about synthesizing a state-feedback controller for a quad copter based on an... more This paper discusses about synthesizing a state-feedback controller for a quad copter based on an optimal linear quadratic control method. The resulting light control system enables the quad copter to maintain stability and to track a reference input. The solution to this control problem involves solving an algebraic Riccati equation. The reference-input tracking capability is simulated to show the capability of the quadcopter flight control system.
Journal of the American Chemical Society, 2018
We disclose unprecedented synergistic bimetallic Ni/Ag and Ni/Cu catalysts for regioselective ,... more We disclose unprecedented synergistic bimetallic Ni/Ag and Ni/Cu catalysts for regioselective ,-diarylation of unactivated alkenes in simple ketimines with aryl halides and arylzinc reagents. The bimetallic synergy, which generates cationic Ni(II) species during reaction, promotes migratory insertion and transmetalation steps, and suppresses -H elimination and crosscoupling, the major side reactions that cause serious problems during alkene difunctionalization. This diarylation reaction proceeds at remote locations to imines to afford, after simple H + workup, diversely substituted ,-diarylketones that are otherwise difficult to access readily with existing methods.
Chemical record (New York, N.Y.), 2018
Transition metal (TM)-catalyzed difunctionalization of unactivated olefins with two carbon-based ... more Transition metal (TM)-catalyzed difunctionalization of unactivated olefins with two carbon-based entities is a powerful method to construct complex molecular architectures rapidly from simple and readily available feedstock chemicals. While dicarbofunctionalization of unactivated olefins has a long history typically with the use of either carbon monoxide to intercept C(sp )-[M] (alkyl-TM) species or substrates lacking in β-hydrogen (β-Hs), development of this class of reaction still remains seriously limited due to complications of β-H elimination arising from the in situ-generated C(sp )-[M] intermediates. Over the years, different approaches have been harnessed to suppress β-H elimination, which have led to the development of various types of olefin dicarbofunctionalization reactions even in substrates that generate C(sp )-[M] intermediates bearing β-Hs with a wide range of electrophiles and nucleophiles. In this review, these developments will be discussed both through the lens o...
Journal of the American Chemical Society, Jan 27, 2018
We disclose a [(PhO)P]/NiBr-catalyzed regioselective β,δ-diarylation of unactivated olefins in ke... more We disclose a [(PhO)P]/NiBr-catalyzed regioselective β,δ-diarylation of unactivated olefins in ketimines with aryl halides and arylzinc reagents. This diarylation proceeds at remote locations to the carbonyl group to afford, after simple H workup, diversely substituted β,δ-diarylketones that are otherwise difficult to access readily with existing methods. Deuterium-labeling and crossover experiments indicate that diarylation proceeds by ligand-enabled contraction of transient nickellacycles.
Journal of the American Chemical Society, Jan 8, 2018
We report a Ni-catalyzed regioselective alkylarylation of vinylarenes with alkyl halides and aryl... more We report a Ni-catalyzed regioselective alkylarylation of vinylarenes with alkyl halides and arylzinc reagents to generate 1,1-diarylalkanes. The reaction proceeds well with primary, secondary and tertiary alkyl halides, and electronically diverse arylzinc reagents. Mechanistic investigations by radical probes, competition studies and quantitative kinetics reveal that the current reaction proceeds via a Ni(0)/Ni(I)/Ni(II) catalytic cycle by a rate-limiting direct halogen atom abstraction via single electron transfer to alkyl halides by a Ni(0)-catalyst.
The Journal of organic chemistry, Mar 15, 2018
We disclose a (terpy)NiBr2-catalyzed reaction protocol that regioselectively difunctionalizes una... more We disclose a (terpy)NiBr2-catalyzed reaction protocol that regioselectively difunctionalizes unactivated olefins with tethered alkyl halides and arylzinc reagents. The reaction shows excellent functional group tolerance (such as ketones, esters, nitriles and halides) and moderate to good level of diastereoselectivity. The current cyclization/cross-coupling also tolerates molecules containing base-sensitive racemizable stereocenters, which are preserved without racemization during reaction. This cyclization/cross-coupling provides rapid access to (arylmethyl)carbo- and heterocyclic scaffolds, which occur widely as structural cores in various natural products and bioactive molecules. In order to show synthetic utility and generality, we have applied this new method in gram-scale quantities to the concise synthesis of six lignan natural products containing three different structural frameworks. We further conducted mechanistic investigations with radical probes and selectivity studies...
Journal of the American Chemical Society, 2017
We disclose a strategy for Ni-catalyzed regioselective dicarbofunctionalization of olefins in sty... more We disclose a strategy for Ni-catalyzed regioselective dicarbofunctionalization of olefins in styrene derivatives by intercepting Heck C(sp 3)-NiX intermediates with arylzinc reagents. This approach utilizes a readily removable imine as a coordinating group that plays a dual role of intercepting oxidative addition species derived from aryl halides and triflates to promote Heck carbometallation, and stabilizing the Heck C(sp 3)-NiX intermediates as transient metallacycles to suppress -hydride elimination and facilitate transmetalation/reductive elimination steps.
Journal of the American Chemical Society, 2017
We present a strategy that difunctionalizes unactivated olefins in 1,2-positions with two carbon-... more We present a strategy that difunctionalizes unactivated olefins in 1,2-positions with two carbon-based entities. This method utilizes alkyl/arylzinc reagents derived from olefintethered alkyl/aryl halides that undergo radical cyclization to generate C(sp 3)-Cu complexes in situ, which are intercepted with aryl and heteroaryl iodides. A variety of (arylmethyl)carbo-and hetero (N, O)-cycles can be synthesized with this new method.
Frontiers in Plant Science
The plant hormone gibberellic acid (GA) is important for plant growth and productivity. Actin-rel... more The plant hormone gibberellic acid (GA) is important for plant growth and productivity. Actin-related proteins (ARPs) also play central roles in plant growth, including cell elongation and development. However, the relationships between ARPs and GA signaling and biosynthesis are not fully understood. Here, we isolated OsGASD, encoding an ARP subunit from rice (Oryza sativa), using the Ac/Ds knockout system. The osgasd knockout (Ko) mutation reduced GA3 content in shoots as well as plant growth and height. However, GA application restored the plant height of the osgasd Ko mutant to a height similar to that of the wild type (WT). Rice plants overexpressing OsGASD (Ox) showed increased plant height and grain yield compared to the WT. Transcriptome analysis of flag leaves of OsGASD Ox and osgasd Ko plants revealed that OsGASD regulates cell development and the expression of elongation-related genes. These observations suggest that OsGASD is involved in maintaining GA homeostasis to regu...
Agronomy
Short crop height is the preferred breeding trait since there is a positive correlation between l... more Short crop height is the preferred breeding trait since there is a positive correlation between lodging resistance and a crop yield increase. Alternative splicing can alter transcriptome diversity and contribute to plant adaptation to environmental stress. We characterized the transcriptomes obtained from dwarf and normal soybean lines derived from a cross of Glycine max var. Peking (G. max) and G. soja var. IT182936 in an F7 RIL population to study the differences between the isoforms. Full-length mRNA derived from leaf tissues was sequenced using the PacBio RSII platform, generating 904,474 circular consensus sequence (CCS) reads. Using the Structural and Quality Annotation of Novel Transcript Isoforms (SQANTI) process, 42,582 and 44,762 high-quality isoforms, and 91 and 179 polished low-quality isoforms were obtained in dwarf and normal cells, respectively. As a result, 832 and 36,772 nonredundant transcripts were generated. Approximately 30% of the identified genes were estimate...
Frontiers in Genetics, 2022
In cultivated plants, shoot morphology is an important factor that influences crop economic value... more In cultivated plants, shoot morphology is an important factor that influences crop economic value. However, the effects of gene expression patterns on shoot morphology are not clearly understood. In this study, the molecular mechanism behind shoot morphology (including leaf, stem, and node) was analyzed using RNA sequencing to compare weedy (creeper) and cultivar (stand) growth types obtained in F7 derived from a cross of wild and cultivated soybeans. A total of 12,513 (in leaves), 14,255 (in stems), and 11,850 (in nodes) differentially expressed genes were identified among weedy and cultivar soybeans. Comparative transcriptome and expression analyses revealed 22 phytohormone-responsive genes. We found that GIBBERELLIN 2-OXIDASE 8 (GA2ox), SPINDLY (SPY), FERONIA (FER), AUXIN RESPONSE FACTOR 8 (ARF8), CYTOKININ DEHYDROGENASE-1 (CKX1), and ARABIDOPSIS HISTIDINE KINASE-3 (AHK3), which are crucial phytohormone response genes, were mainly regulated in the shoot of weedy and cultivar type...
Plant Signaling & Behavior, 2021
ABSTRACT Selaginella tamariscina is a lycophyta species that survives under extremely dry conditi... more ABSTRACT Selaginella tamariscina is a lycophyta species that survives under extremely dry conditions via the mechanism of resurrection. This phenomenon involves the regulation of numerous genes that play vital roles in desiccation tolerance and subsequent rehydration. To identify resurrection-related genes, we analyzed the transcriptome between dehydration conditions and rehydration conditions of S. tamariscina. The de novo assembly generated 124,417 transcripts with an average size of 1,000 bp and 87,754 unigenes. Among these genes, 1,267 genes and 634 genes were up and down regulated by rehydration compared to dehydration. To understand gene function, we annotated Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The unigenes encoding early light-inducible protein (ELIP) were down-regulated, whereas pentatricopeptide repeat-containing protein (PPR), late embryogenesis abundant proteins (LEA), sucrose nonfermenting protein (SNF), trehalose phosphate phosphatase (TPP), trehalose phosphate synthase (TPS), and ABC transporter G family (ABCG) were significantly up-regulated in response to rehydration conditions by differentially expressed genes (DEGs) analysis. Several studies provide evidence that these genes play a role in stress environment. The ELIP and PPR genes are involved in chloroplast protection during dehydration and rehydration. LEA, SNF, and trehalose genes are known to be oxidant scavengers that protect the cell structure from the deleterious effect of drought. TPP and TPS genes were found in the starch and sucrose metabolism pathways, which are essential sugar-signaling metabolites regulating plant metabolism and other biological processes. ABC-G gene interacts with abscisic acid (ABA) phytohormone in the stomata opening during stress conditions. Our findings provide valuable information and candidate resurrection genes for future functional analysis aimed at improving the drought tolerance of crop plants.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
The study found that community livelihood has dependent on the traditional subsistence agricultur... more The study found that community livelihood has dependent on the traditional subsistence agriculture and use of forest resource. Dependency on the natural resource was found to be high and use of alternative source of energy is low which had adverse impact on the forest.Bufferzone programme appears to not to decrease need pressure. Distributions of Bufferzone forest resources were found to be unequal among the households.Information on 70 household was gathered to tie up with vegetation study. For the tree species 12 sample plots, 24 plots for shrubs and herbs were studied. Of these 2 tree species, 22 shrubs and 20 herbs were studied. Density, species diversity, IVI, basal area, volume, biomass and annual yield of plant were low. Regeneration of plant species was low because anthropogenic pressure on forest of Bufferzone found to be high.
Indian Journal of Genetics and Plant Breeding, 2020
Soybean cyst nematode (SCN) is one of the most damaging pest of soybean. Discovery and characteri... more Soybean cyst nematode (SCN) is one of the most damaging pest of soybean. Discovery and characterization of the genes involved in SCN resistance are important in soybean breeding. Soluble NSF attachment protein (SNAP) genes are related to SCN resistance in soybean. SNAP genes include five gene families, and 2 haplotypes of exons 6 and 9 of SNAP18 are considered resistant to the SCN. In present study the haplotypes of GmSNAP18 were surveyed and chacterized in a total of 60 diverse soybean genotypes including Korean cultivars, landraces, and wild-types. The target region of exons 6 and 9 in GmSNAP18 region was amplified and sequenced to examine nucleotide variation. Characterization of 5 haplotypes identified in present study for the GmSNAP18 gene revealed two haplotypes as resistant, 1 as susceptible and two as novel. A total of twelve genotypes showed resistant haplotypes, and 45 cultivars were found susceptible. Interestingly, the two novel haplotypes were present in 3 soybean lines...
Organic Letters, 2020
We describe herein a Cu(OTf) 2 catalyzed oxidative arylation of a tertiary carbon-containing subs... more We describe herein a Cu(OTf) 2 catalyzed oxidative arylation of a tertiary carbon-containing substrates including aryl malononitriles, 3-aryl benzofuran-2-ones, and 3-aryl oxindoles. In some cases, the nitrile groups of the aryl malononitriles undergo further reactions leading to lactones or imines. These reaction conditions are applicable for a range of arenes, including phenols, anilines, anisoles and heteroarenes. Mechanistic studies support the formation of a cationic intermediate via a two-electron oxidation.
ACS Catalysis, 2019
All the reactions were set up inside a nitrogen-filled glovebox and all the chemicals were handle... more All the reactions were set up inside a nitrogen-filled glovebox and all the chemicals were handled under nitrogen atmosphere unless stated otherwise. All the glassware including the 4-dram, 1-dram borosilicate (Kimble-Chase) vials, and pressure vessels were properly dried in an oven before use. Bulk solvents were obtained from EMD, anhydrous solvents (DMF, DMA, DMSO, NMP, dioxane, toluene, MeCN) were obtained from Sigma-Aldrich and were used directly without further purification. Deuterated solvents were purchased from Sigma-Aldrich. NiCl2 was purchased from Alfa-Aesar. 1 H, 13 C and 19 F NMR spectra were recorded on a Bruker instrument (300, 75 and 282 MHz respectively) and internally referenced to the residual solvent signals of CDCl3 for 1 H and 13 C NMR, and C6F6 for 19 F NMR at 7.26 ppm, 77.16 ppm and −164.9 ppm respectively. The chemical shifts of NMR and the coupling constants (J) for 1 H, 13 C and 19 F NMR are reported in δ parts per millions (ppm) and in Hertz, respectively. The following conventions are used for multiplicities: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; dd, doublet of doublet; s, br, singlet broad; ddd, doublet of doublet of doublet. High resolution mass spectra of new compounds were recorded at the mass spectrometry facility, Department of Chemistry and Chemical Biology, University of New Mexico (UNM). All NMR spectra were collected at Department of Chemistry and Chemical Biology, UNM. The X-ray data were measured on a Bruker Kappa APEXII Duo system equipped with a fine-focus sealed tube (Mo Kα, λ = 0.71073 Å) and a graphite monochromator at the X-ray facility at the University of Virginia. Infrared (IR) spectra were recorded on Bruker Alpha-P ATR-IR at UNM and νmax is reported in cm-1 at UNM. 2. Experimental Section 2.1. Preparation of Substrates ethyl 2-cyanopent-4-enoate was prepared following literature procedure. 1
This paper discusses about synthesizing a state-feedback controller for a quad copter based on an... more This paper discusses about synthesizing a state-feedback controller for a quad copter based on an optimal linear quadratic control method. The resulting light control system enables the quad copter to maintain stability and to track a reference input. The solution to this control problem involves solving an algebraic Riccati equation. The reference-input tracking capability is simulated to show the capability of the quadcopter flight control system.
Journal of the American Chemical Society, 2018
We disclose unprecedented synergistic bimetallic Ni/Ag and Ni/Cu catalysts for regioselective ,... more We disclose unprecedented synergistic bimetallic Ni/Ag and Ni/Cu catalysts for regioselective ,-diarylation of unactivated alkenes in simple ketimines with aryl halides and arylzinc reagents. The bimetallic synergy, which generates cationic Ni(II) species during reaction, promotes migratory insertion and transmetalation steps, and suppresses -H elimination and crosscoupling, the major side reactions that cause serious problems during alkene difunctionalization. This diarylation reaction proceeds at remote locations to imines to afford, after simple H + workup, diversely substituted ,-diarylketones that are otherwise difficult to access readily with existing methods.
Chemical record (New York, N.Y.), 2018
Transition metal (TM)-catalyzed difunctionalization of unactivated olefins with two carbon-based ... more Transition metal (TM)-catalyzed difunctionalization of unactivated olefins with two carbon-based entities is a powerful method to construct complex molecular architectures rapidly from simple and readily available feedstock chemicals. While dicarbofunctionalization of unactivated olefins has a long history typically with the use of either carbon monoxide to intercept C(sp )-[M] (alkyl-TM) species or substrates lacking in β-hydrogen (β-Hs), development of this class of reaction still remains seriously limited due to complications of β-H elimination arising from the in situ-generated C(sp )-[M] intermediates. Over the years, different approaches have been harnessed to suppress β-H elimination, which have led to the development of various types of olefin dicarbofunctionalization reactions even in substrates that generate C(sp )-[M] intermediates bearing β-Hs with a wide range of electrophiles and nucleophiles. In this review, these developments will be discussed both through the lens o...
Journal of the American Chemical Society, Jan 27, 2018
We disclose a [(PhO)P]/NiBr-catalyzed regioselective β,δ-diarylation of unactivated olefins in ke... more We disclose a [(PhO)P]/NiBr-catalyzed regioselective β,δ-diarylation of unactivated olefins in ketimines with aryl halides and arylzinc reagents. This diarylation proceeds at remote locations to the carbonyl group to afford, after simple H workup, diversely substituted β,δ-diarylketones that are otherwise difficult to access readily with existing methods. Deuterium-labeling and crossover experiments indicate that diarylation proceeds by ligand-enabled contraction of transient nickellacycles.
Journal of the American Chemical Society, Jan 8, 2018
We report a Ni-catalyzed regioselective alkylarylation of vinylarenes with alkyl halides and aryl... more We report a Ni-catalyzed regioselective alkylarylation of vinylarenes with alkyl halides and arylzinc reagents to generate 1,1-diarylalkanes. The reaction proceeds well with primary, secondary and tertiary alkyl halides, and electronically diverse arylzinc reagents. Mechanistic investigations by radical probes, competition studies and quantitative kinetics reveal that the current reaction proceeds via a Ni(0)/Ni(I)/Ni(II) catalytic cycle by a rate-limiting direct halogen atom abstraction via single electron transfer to alkyl halides by a Ni(0)-catalyst.
The Journal of organic chemistry, Mar 15, 2018
We disclose a (terpy)NiBr2-catalyzed reaction protocol that regioselectively difunctionalizes una... more We disclose a (terpy)NiBr2-catalyzed reaction protocol that regioselectively difunctionalizes unactivated olefins with tethered alkyl halides and arylzinc reagents. The reaction shows excellent functional group tolerance (such as ketones, esters, nitriles and halides) and moderate to good level of diastereoselectivity. The current cyclization/cross-coupling also tolerates molecules containing base-sensitive racemizable stereocenters, which are preserved without racemization during reaction. This cyclization/cross-coupling provides rapid access to (arylmethyl)carbo- and heterocyclic scaffolds, which occur widely as structural cores in various natural products and bioactive molecules. In order to show synthetic utility and generality, we have applied this new method in gram-scale quantities to the concise synthesis of six lignan natural products containing three different structural frameworks. We further conducted mechanistic investigations with radical probes and selectivity studies...
Journal of the American Chemical Society, 2017
We disclose a strategy for Ni-catalyzed regioselective dicarbofunctionalization of olefins in sty... more We disclose a strategy for Ni-catalyzed regioselective dicarbofunctionalization of olefins in styrene derivatives by intercepting Heck C(sp 3)-NiX intermediates with arylzinc reagents. This approach utilizes a readily removable imine as a coordinating group that plays a dual role of intercepting oxidative addition species derived from aryl halides and triflates to promote Heck carbometallation, and stabilizing the Heck C(sp 3)-NiX intermediates as transient metallacycles to suppress -hydride elimination and facilitate transmetalation/reductive elimination steps.
Journal of the American Chemical Society, 2017
We present a strategy that difunctionalizes unactivated olefins in 1,2-positions with two carbon-... more We present a strategy that difunctionalizes unactivated olefins in 1,2-positions with two carbon-based entities. This method utilizes alkyl/arylzinc reagents derived from olefintethered alkyl/aryl halides that undergo radical cyclization to generate C(sp 3)-Cu complexes in situ, which are intercepted with aryl and heteroaryl iodides. A variety of (arylmethyl)carbo-and hetero (N, O)-cycles can be synthesized with this new method.