1,721,324 research outputs found

    AZIRIDINYL ANIONS: GENERATION, REACTIVITY, AND SYNTHETIC APPLICATIONS

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    The high synthetic usefulness of aziridines has been often confined to their electrophilic nature, undergoing nucleophilic ring-opening reactions, as usually taught in organic chemistry courses. The aim of this review is to highlight other aspects of aziridine reactivity, now well out of their infancy. Indeed, aziridines can be easily metalated, generating the corresponding aziridinyl anions, which could act as nucleophiles leaving the three-membered ring functionality intact or, under certain circumstances, as carbenoids thus disclosing an interesting reactional scenery. Even if the reactivity of aziridinyl anions closely mirrors that of the corresponding oxiranyl anions, the investigations of the last 10 years demonstrated that additional factors should be taken into consideration when the generation of metalated aziridines is concern

    Anatomy of Long-Lasting Love Affairs with Lithium Carbenoids: Past and Present Status and Future Prospects

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    After a long adolescence, the chemistry of lithium carbenoids has currently been entering its maturity bringing a dowry of a more in-depth and less empirical knowledge of the structure and configurational stability of such double-faced intermediates; this, thanks in particular to the synergistic and harmonic cooperation between calculations and the most modern NMR techniques now at our disposal. Such a knowledge has stimulated the development of fruitful stereoselective applications in the field of organic synthesis providing as well a rationale to observed selectivities. Such aspects together with the role played by aggregation and solvation on the structure-reactivity relationship have been highlighted throughout this Minireview with selected examples extracted from recent literature

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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