6 resultados para Hatfield, Henry Drury, 1875-1962
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During the research that it is summarized in the present memory, the activation of enals via iminium ion catalysis in different transformations has been studied. Firstly, a 1,3-dipolar cycloaddition between stable azomethine ylides and a,b-unsaturated aldehydes catalyzed by a chiral imidazolidinone derivative has been optimized. Employing this methodology we have synthesized a large range of densely substituted pyrroloisoquinolines and pyrrolophthalazines with good yields and high values of diastereo- and enantioselectivity. Moreover, a mechanistic study has been carried out based on DFT calculations and experimental data which have allowed us to propose that the (3+2) cycloaddition reaction follows a sequential Michael addition/Mannich cyclization pathway. The formation of the iminium ion as a result of the condensation between the a,b-unsaturated aldehyde and the catalyst plays an essential role, regarding both reactivity and stereoselectivity. On the other hand we have developed a methodology to carry out a cascade Michael/Henry reaction followed by a sequential dehydration. Starting from simple substrates (2-nitromethylacrilates and a,b-unsaturated aldehydes) and employing a prolinol-derivative catalyst a series of quiral nitrocyclohexadienes have been synthesized.
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3 cartas (manuscritas) ; entre 220x280mm y 160x220mm. Caja 1 - Carpeta 48
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12 cartas (mecanografiadas) ; entre 215x315mm y 215x157mm. Ubicación: Caja 1 - Carpeta 53
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8 cartas (mecanografiadas y manuscritas); entre 150x210mm y 215x275mm .- 1 Felicitación de Navidad (manuscrita y sin fecha) ; 110mmx160mm
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11 cartas (mecanografiadas y manuscritas); entre 170x215mm y 215x315mm
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[es]organización del trabajo en la industria del automovil en el s. XX.