J. Cristobal Lopez

Bio: J. Cristobal Lopez is an academic researcher from Spanish National Research Council. The author has contributed to research in topics: Radical cyclization & Glycosyl. The author has an hindex of 24, co-authored 168 publications receiving 2263 citations. Previous affiliations of J. Cristobal Lopez include North Carolina State University & Durham University.

Synthesis and conformational and biological aspects of carbasugars.

Abstract: This review covers the progress made in the chemistry, synthesis and biology of carbasugars until May 2004. It includes the extensively studied carbapyranoses as well as the scarcely considered carbafuranoses. Specific topics discussed include the natural occurrence of carbasugars, biosynthesis and biological activity of carbasugars, conformational analysis of carbasugars, and the compilation of synthetic methods of carbafuranoses and carbapyranoses.

Synthesis of a 28-mer oligosaccharide core of Mycobacterial lipoarabinomannan (LAM) requires only two n-pentenyl orthoester progenitors

Abstract: Regioselective glycosidation of acceptor polyols greatly reduces the number of orthogonal protecting groups that are normally required for conventional syntheses of highly branched oligosaccharides. The MATCH between a donor and one of the many-OHs is the basis of a simple, ready synthesis of the 28-mer oligosaccharide described in this manuscript. The strategy relies heavily upon the unique interplay between n-pentenyl orthoesters (NPOEs), n-pentenyl glycosides, ytterbium triflate, and N-iodosuccinimide which allows exquisite, high-yielding regio- and chemoselective glycosylations. The NPOEs, effective as mannose or arabinose donors, are the sole sources of all saccharide components of the lipoarabinomannan oligosaccharide. Once considerable systematic research had been invested, the 12-mer mannan, 92, and 16-mer capped arabinan, 91, domains can be rapidly assembled in 300 mg and 1 g quantities, respectively, using conventional laboratory equipment. The 28-mer, 93 (MW = 11122.54) is, as far as we are aware of, the largest hetero-oligosaccharide that has been synthesized.

The Sonogashira Reaction: A Booming Methodology in Synthetic Organic Chemistry†

Abstract: 3.7. Palladium Nanoparticles as Catalysts 888 3.8. Other Transition-Metal Complexes 888 3.9. Transition-Metal-Free Reactions 889 4. Applications 889 4.1. Alkynylation of Arenes 889 4.2. Alkynylation of Heterocycles 891 4.3. Synthesis of Enynes and Enediynes 894 4.4. Synthesis of Ynones 896 4.5. Synthesis of Carbocyclic Systems 897 4.6. Synthesis of Heterocyclic Systems 898 4.7. Synthesis of Natural Products 903 4.8. Synthesis of Electronic and Electrooptical Molecules 906

Domino Reactions in Organic Synthesis

Abstract: Introduction Cationic domino reactions Anionic domino reactions Radical domino reactions Pericyclic domino reactions Photochemically induced domino processes Transition metal catalysis Domino reactions initiated by oxidation or reduction Enzymes in domino reactions Multicomponent reactions Special techniques in domino reactions

Recent advances in Sonogashira reactions

Abstract: The coupling of aryl or vinyl halides with terminal acetylenes catalysed by palladium and other transition metals, commonly termed as Sonogashira cross-coupling reaction, is one of the most important and widely used sp2–sp carbon–carbon bond formation reactions in organic synthesis, frequently employed in the synthesis of natural products, biologically active molecules, heterocycles, molecular electronics, dendrimers and conjugated polymers or nanostructures. This critical review focuses on developments in the Sonogashira reaction achieved in recent years concerning catalysts, reaction conditions and substrates (352 references).

New principles for glycoside-bond formation.

Abstract: Increased understanding of the important roles that oligosaccharides and glycoconjugates play in biological processes has led to a demand for significant amounts of these materials for biological, medicinal, and pharmacological studies. Therefore, tremendous effort has been made to develop new procedures for the synthesis of glycosides, whereby the main focus is often the formation of the glycosidic bonds. Accordingly, quite a few review articles have been published over the past few years on glycoside synthesis; however, most are confined to either a specific type of glycoside or a specific strategy for glycoside synthesis. In this Review, new principles for the formation of glycoside bonds are discussed. Developments, mainly in the last ten years, that have led to significant advances in oligosaccharide and glycoconjugate synthesis have been compiled and are evaluated.