Manuel Muñoz-Dorado

Silver-mediated synthesis of heterocycles.

2.1. Oxygen Nucleophiles 3174 2.2. Nitrogen Nucleophiles 3177 3. Ag(I)-Mediated Addition of Nucleophiles to Allenes 3178 3.1. Oxygen Nucleophiles 3178 3.1.1. Allenic Alcohols 3178 3.1.2. Allenic Aldehydes and Ketones 3179 3.1.3. Allenic Acids 3180 3.2. Nitrogen Nucleophiles 3180 3.2.1. Allenic Amines 3180 3.2.2. Allenic Sulfonamides 3182 3.2.3. Allenic Carbamates 3182 3.2.4. Allenic Amides 3182 3.2.5. Allenic Oximes 3183 4. Ag(I)-Mediated Additions to Alkenes 3183 5. Ag(I)-Mediated Cycloaddition Reactions 3185 5.1. 1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides 3185

Pterocarpans: interesting natural products with antifungal activity and other biological properties

Among the phytoalexins with the highest antifungal activity is the isoflavonoid based group of pterocarpans. Here, we present a comprehensive inventory of the structures and sources of pterocarpans, and summarize some of their most interesting biological activities.

Ti-Catalyzed Homolytic Opening of Ozonides: A Sustainable C–C Bond-Forming Reaction

The unprecedented homolytic opening of ozonides promoted and catalyzed by titanocene(III) is reported. This novel reaction proceeds at room temperature under neutral, mild conditions compatible with many functional groups and provides carbon radicals suitable to form C-C bonds via both homocoupling and cross-coupling processes. The procedure has been advantageously exploited for the straightforward synthesis of the natural product brittonin A.

Saikosaponins from roots of Bupleurum gibraltaricum and Bupleurum spinosum.

Two new saikosaponins have been identified in the butanolic fraction of the ethanol extract of the roots of Bupleurum spinosum: 3beta,16alpha,23,28-tetrahydroxyoleana-11,13(18)-dien- 30-oic acid 3-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-fucopyranoside, and 3beta,16alpha,23,28,30-pentahydroxyoleana-11,13(18)-diene 3-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-fucopyranoside. 3Beta,16beta,23-trihydroxy-13,28-epoxyolean-11-ene 3-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 3)-beta-D-fucopyranoside was also isolated, and this structure agreed with the one proposed for bupleuroside I, but their spectroscopic data have not been described until now. From the same fraction of the roots of Bupleurum gibraltaricum, the known compound buddlejasaponin IV has been isolated as the predominant component (90%). Structures were elucidated using spectroscopic analysis, specially 2D-NMR experiments.

A concise and diastereoselective total synthesis of cis and trans-pterocarpans

A new strategy for the diastereoselective and convergent synthesis of pterocarpans which is able to control the relative stereochemistry of the molecule through allylation of aromatic aldehydes with cyclic allylsiloxanes is described.

Essential Oil Composition of Sideritis pusilla (Lange) Pau ssp.

Abstract The quantitative composition of the essential oils from several subspecies, varieties and populations of Sideritis pusilla (Lange) Pau (Lamiaceae), analyzed by GC and GC/MS, is reported. Monoterpene hydrocarbons, alcohols, sesquiterpenes and diterpenes were the main constituents in all samples. Among these, α-pinene (7.1–25.4%), sabinene (5.9–20.4%), fenchone (0.9–19.3%), limonene (1.2–7.4%) and 1,8-cineole (1.8–15.6%) were the major compounds. The results confirm that there are differences between varieties and subspecies, while cluster analysis revealed that the oil composition potentially has chemotaxonomical significance for this taxon.

Reaction of benzoxasilocines with aromatic aldehydes: Synthesis of homopterocarpans

Condensation of 2H-benzo[g][1,2]oxasilocines with aromatic aldehydes in the presence of boron trifluoride affords mixtures of cis/trans 2-phenyl-3-vinylchromans with moderate yields. These can be transformed into homopterocarpans, a synthetic group of substances homologous to the natural isoflavonoid pterocarpans.

Stereoselective Synthesis of Natural Products Promoted by Titanocene(III)

Abstract The use of radical reactions in organic synthesis is increasing every year. Bis(cyclopentadienil)titanium(III) chloride [Cp2TiCl] promotes and catalyzes several transformations under mild conditions compatible with several functional groups. Due to its power as a mild single-electron transfer reagent, Cp2TiCl has become a formidable tool in organic synthesis. Thus, this catalyst is being increasingly used in the synthesis of complex multifunctional molecules, mainly natural products and related compound useful in pharmacology. This chapter will include a comprehensive review of those works on Cp2TiCl-mediated synthesis of natural products published from 2006 onward, as there is a previous comprehensive review covering the subject until 2005. The biosynthetic origin of the natural products here reported has been chosen as the method to classify those molecules for which a synthesis is presented. Terpenoids constitute the class of natural products with more examples in this field (Rosales et al., 2015; Morcillo et al., 2014; Rosales et al., 2015; Fernandez-Mateos et al., 2011; Nugent et al., 1988; RajanBabu et al., 1989; RajanBabu et al., 1990; RajanBabu et al., 1994; Justicia et al., 2009; Jimenez et al., 2010) [2] , [3] , [4] , [5] , [6] , [7] , [8] followed by polyketides (Fernandez-Mateos et al., 2013; Lee et al., 1992; Dixit et al., 2007; Mori et al., 1997; Yadav et al., 2005; Mandal et al., 2010; Gansauer et al., 2009) [9] , [10] , [11] , [12] and phenylpropanoids (Garcia Santos et al., 2015; Barrero et al., 2001) [13] , [14] . Moreover, some nitrogen-containing substances have also been prepared by titanocene(III)-based methods, especially antibiotics and alkaloids (Bermejo et al., 2006; Perez Morales et al., 2013) [15,16]. Finally, new methodologies applying Cp2TiCl catalysis, which can potentially lead to complex natural products, are also shown (Gianino et al., 2014) [106d].