Catalytic Asymmetric Additions of in situ Generated Functionalized Zinc Reagents to Aldehydes

Enantioenriched secondary alcohols are ubiquitous moieties in natural products. The current methods to achieve their synthesis often times rely on complicated synthesis and isolation of fairly reactive and unstable organometallic reagents. To address these issues our group developed one-pot catalytic asymmetric methods toward the synthesis of E-allylic alcohols and diarylmethanols employing in situ synthesized functionalized Lewis acidic zinc reagents in the presence of chiral amino alcohols ligands. However, analogous methods for the synthesis of equally useful Z-allylic alcohols and diheteroaryl methanols were lacking. The reason why this task was more challenging is because en route toward the synthesis of the appropriate functionalized zinc reagents a Lewis acidic byproduct (lithium halide) was generated which would catalyze a racemic background reaction. The problem was addressed finding an additive, tetraethylethylenediamine (TEEDA), which could selectively inhibit the background reaction discriminating between the two Lewis acidic species present in the flask. The asymmetric addition could now take place giving the product in high yield and ee in one-pot. In the first chapter a novel catalytic asymmetric method for the synthesis of (Z)-disubstituted allylic alcohols is presented. Our one-pot procedure entails hydroboration of chloro alkynes and addition of a hydride source (t-BuLi), which results in formation of a (Z)-alkenylborane. Boron to zinc transmetalation of the alkenyl group with ZnEt2, addition of a chiral ligand, the inhibitor (TEEDA) and the substrate aldehyde results in formation of (Z)-allylic alcohols with excellent ee’s. In the effort of streamlining the synthesis of compounds with multiple stereocenters, tandem protocols were devised to synthesize cyclopropyl- and epoxy-alcohols. Finally a brief study for the synthesis of racemic Z-trisubstituted allylic alcohols is presented. In the second chapter we describe a method for the synthesis of diarylmethanols generating the desired arylzinc reagent in situ and adding it to both aromatic and heteroaromatic aldehydes. The one pot procedure entails lithium/halogen exchange, transmetallation with a zinc species, with generation of undesired LiCl that can be sequestered in situ by an additive (TEEDA). The functionalized zinc reagent, in the presence of the chiral catalyst (–)-MIB, adds to a variety of aromatic and heteroaromatic aldehydes in excellent ee, thus enabling the formation of highly desirable diheteroarylmethanols as well as many other compounds

El paisaje en el texto. El paisaje del texto. Elementos petrarquistas en la poesía de Ramón López Velarde

A perusal of the Petrarch’s Canzoniere reveals the text as the place where the self builds and structures itself, following the typical oscillation of eroticism and love. From this interpretation, the paper aims to identify, in Ramón López Velarde’s poetic use of settings, similarities of traits and functions with the same element in the Petrarchan poetry. The peculiar way settings are used allows to focus a logic that deeply permeates the whole text, providing suitable instruments to revalue the way the original Petrarchan lesson survives in modern and contemporary poetry.Una atenta lectura del Canzoniere de Petrarca revela el texto como el lugar donde el yo se construye y estructura, siguiendo el movimiento oscilatorio propio del sentimiento erótico-amoroso. A partir de esta perspectiva, el artículo se propone reconocer, en las referencias al paisaje en la poesía de Ramón López Velarde, características y funciones análogas a las que el mismo elemento tiene en la obra de Petrarca. El peculiar modo de empleo del paisaje aclara una lógica que condiciona de manera más amplia el entero tejido textual, proporcionando las herramientas adecuadas para volver a evaluar las modalidades de supervivencia, en la poesía moderna y contemporánea, de la lección petrarquesca origina

José Asunción Silva: para una geografía simbólica de su poesía

The study’s aim is to focalize Silva’s imaginary, analyzing the symbolic relations that are determined at the level of the settings, both in El libro de versos and Gotas amargas. Building a poetry defined by a permanent oxymorical opposition of different symbolical terms, Silva organizes the same conflict at the level of the settings, making them functional in order to satisfy his personal expressive needs.El estudio se propone enfocar el imaginario de José Asunción Silva analizando las relaciones simbólicas que se establecen entre los espacios literarios, en El libro de versos y Gotas amargas. Al construir una poesía caracterizada por una permanente oposición oximorónica de diferentes términos simbólicos, Silva organiza en el plano de las ambientaciones el mismo contraste, haciéndolas directamente funcionales a sus personales necesidades expresivas

La mancha y el ejemplo. Pedro Figari y la óptica de la modernidad

This paper aims to reconsider the eccentric intellectual – visual, literary and philosophical – production of the Uruguayan Pedro Figari in light of the ideological background that animates it and founds this particular Figarian project: to product universally shared forms which contribute to the affirmation of a unique idea of Latin-American modernity. A project in which, in the intersection of figurative stylization, rhetoric of example and utopian narrative, modernity still results linked to a subalternity strictly related to a colonial heritage.El estudio pretende repensar la excéntrica producción intelectual – visual, literaria y filosófica – del uruguayo Pedro Figari, a la luz del substrato ideológico que la anima y que funda ese particular proyecto figariano de producir formas universales y compartidas que contribuyan a la afirmación de una idea única de modernidad latinoamericana. Proyecto donde, en el cruce de la estilización figurativa, de la retórica del ejemplo y de la narrativa utópica, lo moderno resulta todavía atado a una subalternidad cargada de herencias coloniales.

Alle soglie dell'osceno. Poetiche della profanazione in Sara de Ib\ue1\uf1ez e Alejandra Pizarnik

Partendo dall'analisi di Adorno sulla natura enigmatica dell'estetica moderna, l'articolo vuole analizzare le forme dell'enigma nelle opere delle poetesse Sara de Ib\ue1\uf1ez e Alejandra Pizarnik

La imaginación del museo. Francisco Xavier Clavigero y la reconfiguración del archivo virreinal

This essay analyzes the nature of the "novohispano" archive, its crossroads and textures, focusing in the work of Francisco Clavigero, its collection and its knowledge of the objects and materials of ancient Mexico. By reimagining this past, Clavigero reorients various objects and materials, discusses the very nature of the historical discourse and shows how the "criollo" archive is formed

La mancha y el ejemplo. Pedro Figari y la \uf3ptica de la modernidad

No obstante su frecuente inclusi\uf3n en los rangos de los movimientos de vanguardias rioplatenses de las primeras d\ue9cadas del siglo XX, la obra del uruguayo Pedro Figari aparece, despu\ue9s de una observaci\uf3n atenta, sin duda exc\ue9ntrica si parangonada con aquellas de sus contempor\ue1neos. El art\uedculo se propone entonces repensar su producci\uf3n intelectual \u2013 visual, literaria y filos\uf3fica \u2013 a la luz del substrato ideol\uf3gico que la anima y funda ese particular proyecto figariano de producir formas universales y compartidas que contribuyan a la afirmaci\uf3n de una idea \ufanica de modernidad latinoamericana

El juramento y la historia. Sobre Oblivion de Edda Fabbri

The genre of testimony troubles any attempt at classification and categorization. From a linguistic perspective, testimonial language seems to be suspended within an aporistic oscillation between the two opposite directions of historiographical objectivity and the first person pre-eminence, which shapes the whole discursive structure and function of this genre. Furthermore, this oscillation between the historiographical form and the writing of the self leads to the dialectical movement between two different kinds of truth: a historical truth \u2013 which is one of the explicit goals of these texts \u2013 as opposed to an aesthetical one, which is another unquestionable concern for this kind of writing. Nevertheless, the oscillation between these two forms of testimony recalls an even more relevant and radical tension, which opposes, on the one hand, the necessity to stick to a traumatic past occupying the entire memory of someone\u2019s subjectivity, and, on the other hand, the imperative to bend the memorial discourse through the possibility to achieve an active intervention in the historical present. Reading Oblivion \u2013 the testimony written by Edda Fabbri, an Uruguayan tupamaro activist, and published for the first time in 2007 \u2013 this paper aims to analyze the dialectical intersection that forms the living substrate of any testimonial writing, in order to point out the real power of testimonial literature, that is, the ethical \u2013 and political \u2013 possibility to actively participate into history.El testimonio se presenta como el lugar de una multiple imposibilidad de categorizaci\uf3n. En su faceta ling\ufc\uedstica, el idioma testimonial aparece en seguida como suspendido en una oscilaci\uf3n apor\uedstica entre las dos caras opuestas e inconciliables del imperativo de la objetividad historiogr\ue1fica y la preeminencia de la primera persona singular que moldea la estructura y el funcionamiento del discurso. Por otro lado, esta divaricaci\uf3n de los textos entre forma historiogr\ue1fica y escritura del yo lleva al enfrentamiento dial\ue9ctico de dos tipolog\uedas diferentes de verdades: la verdad hist\uf3rica, de cuya transmisi\uf3n esta tipolog\ueda de textos se encarga expl\uedcitamente, y una verdad est\ue9tica que parece incuestionable a la hora de abordar esta categor\ueda de escrituras. Sin embargo, estas dos formas de oscilaci\uf3n del testimonio no son sino los fundamentos a partir de los cuales se desarrolla una tensi\uf3n a\ufan m\ue1s radical y relevante: esa tensi\uf3n que ve enfrentarse rec\uedprocamente, por un lado, la adherencia a un pasado traum\ue1tico que ocupa enteramente el espacio subjetivo de la memoria y, por el otro, el imperativo de doblar el discurso memorial para que la escritura del pasado pueda resolverse en las formas de una intervenci\uf3n activa en el presente hist\uf3rico. Leyendo el testimonio de la militante tupamara uruguaya Edda Fabbri, publicado por primera vez en 2007 con el t\uedtulo de Oblivion, el art\uedculo se propone analizar este entramado dial\ue9ctico que forma el substrato vivo de toda escritura testimonial, para destacar, en conclusi\uf3n, las posibilidades \ue9ticas y pol\uedticas de intervenci\uf3n en la historia que la literatura testimonial nos entrega

La operaci\uf3n infinita. Jos\ue9 Lezama Lima y las formas de la Am\ue9rica Latina

El art\uedculo pretende analizar las reflexiones lezamianas en torno a la identidad latinoamericana, estudiando, adem\ue1s, las repercusiones que dichas reflexiones tuvieron en su obra literaria