Publications by authors named "Broggini G"

The coupling between bis(2-oxazolines) and two equivalents of aromatic aldehydes in the presence of catalytic amounts of NiCl affords an ester-imine product in synthetically useful yields. This virtually unknown, 100% atom-economic transformation involves the formal metathesis between the C=N double bond of the bis(2-oxazoline) moiety, which undergoes ring-opening, and the C=O double bond of the aldehyde. The scope of this transformation is studied, and a mechanism is proposed based on DFT calculations.

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A synthetic protocol for the preparation of a new class of morpholino homonucleosides in enantiopure form starting from readily available 1,2-aminoalcohols or glycidol has been developed. Key intermediates of the synthetic sequence are 2-bromomethyl morpholines, diastereoselectively achieved from the corresponding alkenols by palladaelectro-catalyzed alkoxybromination of unactivated alkenes. The so obtained bromo derivatives are in turn susceptible to functionalization with nucleic bases for easy access to morpholino homonucleosides.

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Background: Fruit appearance of apple (Malus domestica Borkh.) is accession-specific and one of the main criteria for consumer choice. Consequently, fruit appearance is an important selection criterion in the breeding of new cultivars.

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Great diversity of shape, size, and skin color is observed among the fruits of different apple genotypes. These traits are critical for consumers and therefore interesting targets for breeding new apple varieties. However, they are difficult to phenotype and their genetic basis, especially for fruit shape and ground color, is largely unknown.

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A phosphine-catalyzed domino assembly of six units of 2-bromomethyl acrylates afforded polyalkenyl adducts containing two cyclohexenyl rings. This reaction occurs under mild conditions providing the final product by formation of seven carbon-carbon bonds and four stereocenters. Experimental and computational studies support an initial dimerization of the substrate, which in turn trimerizes involving two totally regio- and stereocontrolled Diels-Alder cycloadditions.

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A new straightforward approach to 1-aryl-2-aminopropanes using easily accessible substrates has been developed. Simple allyl alcohol is shown to be an ideal synthetic equivalent of the C3 propane-1,2-diylium bis-cation synthon in three-component cascade reactions with arenes and sulfonamide nucleophiles to regioselectively afford 1-aryl-2-aminopropanes. The reaction is catalyzed by Cu(OTf) and is expected to involve a Friedel-Crafts-type allylation of the arene, followed by hydroamination.

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Cisgenesis, the genetic modification of a plant with genes from a sexually compatible plant, was used to confer fire blight resistance to the cultivar 'Gala Galaxy' by amendment of the resistance gene FB_MR5, resulting in the line C44.4.146.

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Article Synopsis
  • This study focuses on the genetic transformation of perennial ryegrass, essential for research, by testing various explants and genotypes for effective callus induction.
  • The researchers successfully transformed callus tissues with plasmids for gene silencing and CRISPR/Cas9 gene editing, resulting in 262 transgenic events using 19 different constructs.
  • The findings demonstrate a new method to broaden the types of ryegrass genotypes that can be transformed, aiding in research and breeding efforts to enhance this crucial grass species used for forage and recreation.
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Genetic modification of apple cultivars through cisgenesis can introduce traits, such as disease resistance from wild relatives, quickly and without crossing. This approach was used to generate the cisgenic apple line C44.4.

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Treatment of 4-(2-hydroaminoalkylidenyl)- and 4-(2-hydroxyalkylidenyl)-substituted isoxazol-5(4)-ones with catalytic amounts of [RuCl(-cymene)], without any additive, afforded pyrazole- and isoxazole-4-carboxylic acids, respectively. The presence of an intramolecular H-bond in these substrates was the key to divert the classical mechanism toward a ring-opening non-decarboxylative path that is expected to generate a vinyl Ru-nitrenoid intermediate, the cyclization of which affords the rearranged products. A gram scale protocol demonstrated the synthetic applicability of this transformation.

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A new Ru(CO)-catalyzed directed alkenylation of 2-carboxaldimine-heterocyclopentadienes has been accomplished. This process allows coupling of furan, pyrrole, indole, and thiophene 2-carboxaldimines with electron-poor alkenes such as acrylates, vinylsulfones, and styrenes. This regio- and chemoselective oxidative C-H coupling does not require the presence of an additional sacrificial oxidant.

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A dimerization/cyclization reaction of 2-benzylamino-phenols for the direct synthesis of the oxazolo-phenoxazine skeleton is reported. The reaction occurs under copper catalysis in the presence of hypervalent iodine(III), giving selectively the 5-oxazolo[4,5-]phenoxazine compounds. The cascade process, which allows the conversion of the substrates into the tetracyclic products, involves three C-H functionalization steps.

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Rapid cycle breeding uses transgenic early flowering plants as crossbreed parents to facilitate the shortening of breeding programs for perennial crops with long-lasting juvenility. Rapid cycle breeding in apple was established using the transgenic genotype T1190 expressing the gene of silver birch. In this study, the genomes of T1190 and its non-transgenic wild-type PinS (F1-offspring of 'Pinova' and 'Idared') were sequenced by Illumina short-read sequencing in two separate experiments resulting in a mean sequencing depth of 182× for T1190 and 167× for PinS.

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Most of the commercial apple cultivars are highly susceptible to fire blight, which is the most devastating bacterial disease affecting pome fruits. Resistance to fire blight is described especially in wild Malus accessions such as M. × robusta 5 (Mr5), but the molecular basis of host resistance response to the pathogen Erwinia amylovora is still largely unknown.

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4,4-Disubstituted 4-isoxazol-5-ones bearing a 1,4-naphthoquinone moiety undergo transformation into different types of benzoindolyl products depending on the different reaction conditions. A decarboxylative ring opening/ring closure promoted by catalytic [Ru(-cymene)Cl] yields benzo[]indole-4,9-diones. Alternatively, hydrogenation reactions provide the conversion of 4-(1,4-naphthoquinone)-substituted isoxazol-5-ones to benzo[]indole compounds, with the level of reduction depending on the substituents present on the ring.

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The palladium-catalyzed aminoazidation of aminoalkenes yielding azidomethyl-substituted nitrogen-containing heterocycles was developed. The procedure requires oxidative conditions and occurs at room temperature in the presence of hydrogen peroxide and NaN as the azide source. These conditions provide selective -cyclization/azidation of the carbon-carbon double bond, furnishing a versatile approach toward five-, six-, and seven-membered heterocyclic rings.

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Breeding for resistance against the destructive fire blight disease of apples is the most sustainable strategy to control the menace of this disease, and has become increasingly important in European apple breeding programs. Since most cultivars are susceptible, wild accessions have been explored for resistance with quantitative trait loci detected in a few wild species. Fire blight resistance of was described following phenotypic evaluations with a C-type strain of , Ea222_JKI, and the detection of a major QTL on chromosome 10 () of this crabapple.

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Pyrimidine-1,3-oxazolidin-2-arylimino hybrids have been synthesized as a new class of antibacterial agents. The synthetic approach exploits a Cu(II)-catalyzed intramolecular halkoxyhalogenation of alkynyl ureas, followed by a Suzuki coupling reaction with 2,4-dimethoxypyrimidin-5-boronic acid. Biological screenings revealed that most of the compounds showed moderate to good activity against two Gram-positive (, ) and three Gram-negative (, , ) pathogenic strains.

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The approach presented here can be applied to reduce the time needed to introduce traits from wild apples into null segregant advanced selections by one-fourth. Interesting traits like resistances to pathogens are often found within the wild apple gene pool. However, the long juvenile phase of apple seedlings hampers the rapid introduction of these traits into new cultivars.

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Phyllosticta ampelicida causes black rot disease of Vitis spp. Genetic homogeneity of pathogen populations was investigated by analyzing the number of haplotypes present in infected samples from Europe and America. The fungus was identified from an analysis of the internal transcribed spacer (ITS)1-ITS2 region, and partial sequences of β-tubulin and calmodulin genes.

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The loop-mediated isothermal amplification (LAMP) allows the rapid and specific amplification of target DNA under isothermal conditions without a prior DNA purification step. Moreover, successful amplifications can be directly evaluated through a color change of the reaction solutions. Here, we describe two LAMP assays for the detection of ochratoxin-A producing black aspergilli isolated from grapes.

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The generation and selection of novel fire blight resistant apple genotypes would greatly improve the management of this devastating disease, caused by Erwinia amylovora. Such resistant genotypes are currently developed by conventional breeding, but novel breeding technologies including cisgenesis could be an alternative approach. A cisgenic apple line C44.

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The expression of the apple scab resistance gene Rvi6 in different apple cultivars and lines is not modulated by biotic or abiotic factors. All commercially important apple cultivars are susceptible to Venturia inaequalis, the causal organism of apple scab. A limited number of apple cultivars were bred to express the resistance gene Vf from the wild apple genotype Malus floribunda 821.

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A highly effective synthesis of haloalkylidene-substituted heterocycles by copper(II)-catalyzed cyclization of alkynyl ureas and secondary amides has been developed. The reaction, which involves a catalytic amount of CuCl2 and a stoichiometric amount of N-halosuccinimide, occurs selectively through an alkoxyhalogenation process. Alternatively, alkoxychlorination and alkoxybromination reactions can be performed working solely with stoichiometric CuCl2 and CuBr2, respectively.

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Article Synopsis
  • Two innovative methods for creating cisgenic apples were developed, focusing on integrating desirable traits without foreign marker genes.
  • The first method involved the incorporation of the MdMYB10 gene to produce red-fleshed apples, confirmed through flowering and successful pollination.
  • The second method utilized a marker-free approach by introducing the scab resistance gene Rvi6 and employing a recombinase system, resulting in resilient apple lines free from selection markers and immune to scab symptoms.
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