Triorganoindium reagents in cross-coupling reactions: transition-metal-free reactions with benzopyranyl acetals and tetrahydroisoquinolines and solid-stable organometallics

Programa Oficial de Doutoramento en Química Ambiental e Fundamental. 5031V01[Abstract] This Thesis presents the development of a new transition-metal-free coupling reaction of triorganoindium reagents with chromene and isochroman acetals under BF3·OEt2 activation. This reaction allows the synthesis of the corresponding 2-substituted 2H-chromenes and 1-substituted isochromans in good yields, in which aryl, heteroaryl, alkynyl, alkenyl, and alkyl groups can be transferred using only 50 mol% of the triorganoindium reagents. As an extension of this methodology, a transition-metal-free coupling reaction of triorganoindium reagents with N-protected tetrahydroisoquinolines (THIQs) under oxidative conditions is presented as well, where different aryl, heteroaryl, alkynyl, benzyl, and alkyl groups can be installed at the C-1 position of the THIQs, using only 50 mol% of the triorganoindium reagent. To demonstrate the synthetic utility of this reaction, it was applied to the synthesis of alkaloid Nuciferine. This Thesis also presents the synthesis and isolation of solid, bench-stable triorganoindium reagents by coordination with 4-dimethylaminopyridine (DMAP). Different R3In·DMAP complexes bearing aryl, heteroaryl, alkynyl, and benzyl groups were prepared and then used in palladium-catalyzed cross-coupling reactions, where they reacted efficiently with diverse electrophiles including aryl, alkenyl, allyl, and benzyl bromides.[Resumen] En esta Tesis se presenta el desarrollo de una nueva reacción de acoplamiento de reactivos triorganoíndicos con acetales de cromeno e isocramano mediante activación con BF3·OEt2 en ausencia de metales de transición. Esta reacción permite la síntesis de los correspondientes 2H-cromenos-2-sustituidos e isocromanos 1-sustituidos en buenos rendimientos, en donde grupos arilo, heteroarilo, alquinilo, alquenilo y alquilo se transfieren empleando solamente un 50 mol% de los reactivos triorganoíndicos. Como extensión de esta metodología, se presenta también la reacción de acoplamiento de reactivos triorganoíndicos con tetrahidroisoquinolinas (THIQs) N-protegidas en condiciones oxidantes y ausencia de metales de transición, en donde grupos arilo, heteroarilo, alquinilo, bencilo, y alquilo se acoplan en la posición C-1 de las THIQs, empleando solamente un 50 mol% del reactivo triorganoíndico. Para demostrar su utilidad sintética, esta nueva reacción se emplea en la síntesis del alcaloide Nuciferina. En esta Tesis también se presenta la síntesis y aislamiento de reactivos triorganoíndicos sólidos y estables mediante coordinación con 4-dimetilaminopiridina (DMAP). Distintos R3In·DMAP con grupos arilo, heteroarilo, alquinilo y bencilo se preparan y son empleados en reacciones de acoplamiento cruzado catalizadas por paladio, donde reaccionan de forma eficiente con distintos electrófilos incluyendo bromuros de arilo, alquenilo, alilo y bencilo.[Resumo] Nesta Tese presentamos o desenvolvemento dunha nova reacción de acoplamento de reactivos triorganoínicos con acetais de cromeno e isocromano pola activación con BF3·OEt2 en ausencia de metais de transición. Esta reacción permite a síntese dos correspondentes 2H-cromenos-2-sustituidos e isocromanos 1-sustituidos en bos rendementos, onde grupos arilo, heteroarilo, alquinilo, alquenilo y alquilo transfírense utilizando só un 50 mol% dos reactivos triorganoíndicos. Como extensión desta metodoloxía, presentamos tamén la reacción de reactivos triorganoíndicos con tetrahidroisoquinolinas N-protegidas, en condicións de oxidación e ausencia de metais de transición en que grupos arilo, heteroarilo, alquinilo, bencilo y alquilo pódense acoplar na posición C-1 das THIQs, utilizando só un 50 mol% dos reactivos triorganoíndicos. Para demostrar a súa utilidade sintética, a reacción emprégase na síntese do alcaloide Nuciferina. Nesta Tese son sintetizados e illados reactivos triorganíndicos sólidos por coordinación con 4-dimetilaminopiridina (DMAP). Varios triorganoíndicos sólidos con grupos arilo, heteroarilo, alquinilo y bencilo prepáranse y son utilizados en reaccións de acoplamento cruzado catalizadas por paladio, reaccionando eficientemente con diferentes electrófilos incluíndo bromuros de arilo, alquenilo, alilo e bencilo

Co-existence in maize supply chains in Spain and Switzerland

The debate about co-existence usually focuses on the situation of neighbouring farms. Organic producers take the position that co-existence affects the whole supply chain. Therefore, this paper compares the maize grain supply chains in Switzerland and Spain in order to identify which factors influence the segregation of genetically modified (GM) maize from non-GM maize, and discusses how organic production copes with the challenge of GM maize. Considerable differences exist between Spain and Switzerland with regard to grain maize as a component of animal feed. In Spain, where GM maize is grown, it is the feed industry that defines standards in the supply chains. Since the trading co-operatives are unable to supply GM-free maize, independent and separate infrastructures have been developed for a GM-free maize supply (e.g. for maize starch). In Switzerland, the retailers define quality standards for suppliers, and these standards exclude the use of GM plants for feed. Therefore, the feed industry has to segregate GM from non-GM feed

Effectiveness of a carbon tax to promote a climate-friendly food consumption

info:eu-repo/semantics/acceptedVersio

Decision making techniques with similarity measures and OWA operators

We analyse the use of the ordered weighted average (OWA) in decision-making giving special attention to business and economic decision-making problems. We present several aggregation techniques that are very useful for decision-making such as the Hamming distance, the adequacy coefficient and the index of maximum and minimum level. We suggest a new approach by using immediate weights, that is, by using the weighted average and the OWA operator in the same formulation. We further generalize them by using generalized and quasi-arithmetic means. We also analyse the applicability of the OWA operator in business and economics and we see that we can use it instead of the weighted average. We end the paper with an application in a business multi-person decision-making problem regarding production management

Trace elements and C and N isotope composition in two mushroom species from a mine-spill contaminated site

Fungi play a key role in the functioning of soil in terrestrial ecosystems, and in particular in the remediation of degraded soils. The contribution of fungi to carbon and nutrient cycles, along with their capability to mobilise soil trace elements, is well-known. However, the importance of life history strategy for these functions has not yet been thoroughly studied. This study explored the soil-fungi relationship of two wild edible fungi, the ectomycorrhizal Laccaria laccata and the saprotroph Volvopluteus gloiocephalus. Fruiting bodies and surrounding soils in a mine-spill contaminated area were analysed. Isotope analyses revealed Laccaria laccata fruiting bodies were 15N-enriched when compared to Volvopluteus gloiocephalus, likely due to the transfer of 15N-depleted compounds to their host plant. Moreover, Laccaria laccata fruiting bodies δ13C values were closer to host plant values than surrounding soil, while Volvopluteus gloiocephalus matched the δ13C composition to that of the soil. Fungal species presented high bioaccumulation and concentrations of Cd and Cu in their fruiting bodies. Human consumption of these fruiting bodies may represent a toxicological risk due to their elevated Cd concentrations

Synthesis of bench-stable solid triorganoindium reagents and reactivity in palladium-catalyzed cross-coupling reactions

[Abstract] Bench-stable solid triorganoindium compounds have been prepared by coordination with 4-(dimethylamino)pyridine (DMAP). The solid R3In(DMAP) complexes are obtained from the corresponding solution of R3In in quantitative yield and can be stored for up to several weeks. These reagents show excellent reactivity in palladium-catalyzed cross-coupling reactions with organic electrophiles.Ministerio de Economía y Competitividad; CTQ2015-68369-PGalicia. Consellería de Cultura, Educación e Ordenación Universitaria; GRC2014/04

Transition-metal-free cross-coupling of indium organometallics with chromene and isochroman acetals mediated by BF3·OEt2

[Abstract] A transition-metal-free coupling of triorganoindium reagents with benzopyranyl acetals mediated by a Lewis acid has been developed. The reaction of R3In with chromene and isochroman acetals in the presence of BF3·OEt2 afforded 2-substituted chromenes and 1-substituted isochromans, respectively, in good yields. The reactions proceed with a variety of triorganoindium reagents (aryl, heteroaryl, alkynyl, alkenyl, alkyl) using only 50 mol % of the organometallic, thus demonstrating the efficiency of these species. Preliminary mechanistic studies indicate the formation of an oxocarbenium ion intermediate in the presence of the Lewis acid.Ministerio de Economía y Competitividad; CTQ2012-31200Ministerio de Economía y Competitividad; CTQ2015-68369-

Diels-alder cycloaddition of 2-azadienes to methyl 2-(2,6-dichlorophenyl)-2H-azirine-3-carboxylate in the synthesis of methyl 4-oxo-1,3-diazabicyclo[4.1.0]heptane-6-carboxylates

A number of fused 4-oxo-1,3-diazabicyclo[4.1.0]heptane-6-carboxylates, a new type of compound, have been obtained by Diels-Alder cycloaddition between nucleophilic 2-azadienes and an electrophilic 2H-azirine. The reactions are completely endo- and regioselective, the azirine being added by its less hindered face to the diene. There are two isomers 7 and 8 formed from dienes 1 due either to isomerization of the cycloadducts 7 and 8 or by isomerization of the C=N bond of the diene during the reaction. The isomer 10 is formed from diene 2e, and a single diastereoisomer structure 4a-i is formed from dienes 11. Some pyrimidones 8a,7c/8c, 7e, 10, 11d have been hydrolyzed leading to functionalised aziridines 12, 13 and 15.Fundação para a Ciência e Tecnologia - POCTI/32723/QUI/2000. FEDER

Cycloaddition of methyl 2-(2,6-dichorophenyl)-2H-azirine-3-carboxylate to electron rich 2-azadienes

Tert-Butyldimethylsililoxy-2-aza-1,3-butadienes react with 2H-azirine 3 leading to Diels-Alder cycloadducts in moderate yields. The reactions are endo- and regio- selective with the azirine being added by its less hindered face. There is only one product in the case of 1b, 4b. There are two isomers (4 and 5) from 1a, 1c and 1d. A different result was obtained with the diene 1e. Diene 1e formed products 4e and 8. Some of compounds 4 and 5 have been hydrolysed leading to functionalized aziridines 7. Compound 8 gave aziridine 9.Fundação para a Ciência e Tecnologia - POCTI/32723/QUI/2000. FEDER