Novel citation-based search method for scientific literature: a validation study.

BACKGROUND: We recently developed CoCites, a citation-based search method that is designed to be more efficient than traditional keyword-based methods. The method begins with identification of one or more highly relevant publications (query articles) and consists of two searches: the co-citation search, which ranks publications on their co-citation frequency with the query articles, and the citation search, which ranks publications on frequency of all citations that cite or are cited by the query articles. METHODS: We aimed to reproduce the literature searches of published systematic reviews and meta-analyses and assess whether CoCites retrieves all eligible articles while screening fewer titles. RESULTS: A total of 250 reviews were included. CoCites retrieved a median of 75% of the articles that were included in the original reviews. The percentage of retrieved articles was higher (88%) when the query articles were cited more frequently and when they had more overlap in their citations. Applying CoCites to only the highest-cited article yielded similar results. The co-citation and citation searches combined were more efficient when the review authors had screened more than 500 titles, but not when they had screened less. CONCLUSIONS: CoCites is an efficient and accurate method for finding relevant related articles. The method uses the expert knowledge of authors to rank related articles, does not depend on keyword selection and requires no special expertise to build search queries. The method is transparent and reproducible.

Intramolecular oxonium ylide formation-[2,3] sigmatropic rearrangement of diazocarbonyl-substituted cyclic unsaturated acetals: a formal synthesis of hyperolactone C.

Rh(II)-catalyzed oxonium ylide formation-[2,3] sigmatropic rearrangement of α-diazo-ß-ketoesters possessing γ-cyclic unsaturated acetal substitution, followed by acid-catalyzed elimination-lactonization, provides a concise approach to 1,7-dioxaspiro[4.4]non-2-ene-4,6-diones. The process creates adjacent quaternary stereocenters with full control of the relative stereochemistry. An unsymmetrical monomethylated cyclic unsaturated acetal leads to hyperolactone C, where ylide formation-rearrangement proceeds with high selectivity between subtly nonequivalent acetal oxygen atoms.

Interactions of marine-derived γ-pyrone natural products with phospholipid membranes.

The sacoglossan mollusc-derived metabolite, tridachiahydropyrone (3), and its proposed biosynthetic precursors (1 and 2) form part of a complex chemical defence system against predators and harmful UV light. Here, we provide supporting biophysical evidence that the metabolites become selectively localised at cell membranes and outline a binding scheme that accommodates the observed data. The possibility that localised lipid domains within the membrane have an effect on the localisation is also addressed.

Chemoselective palladium-catalyzed cyanation of alkenyl halides.

A palladium-catalyzed cyanation of alkenyl halides using acetone cyanohydrin is described. A number of structurally diverse alkenylic nitrile containing compounds was prepared in one step under optimized conditions. The reaction proved to be efficient, chemoselective, easy to perform, and tolerant of a number of functional groups.