Míriam Álvarez-Corral

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 Straightforward Synthesis of Exocyclic Allenes

Exocyclic allenes constitute useful building blocks in organic synthesis and have recently been identified as key intermediates in the synthesis of natural products. Here the first general method for the most straightforward synthesis of exocyclic allenes reported to date is presented. This method is based on the Barbier-type cyclization of propargyl halides catalyzed by titanium; a safe, abundant, and ecofriendly metal. The reaction proceeds under mild conditions compatible with different functional groups and provides good yields of five-, six-, and seven-membered carbocycles and nitrogen-containing heterocycles bearing an exocyclic allene group. Experimental evidence supporting the proposed reaction mechanism is also provided. Moreover, this procedure can be carried out in an enantioselective manner by using chiral titanocene(III) catalysts. The utility of this method has been proved in the synthesis of the natural alkaloid stemoamide.

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.

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.

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.

Nuevos Recursos Docentes Aplicados en Asignaturas de la Titulación de Ciencias Ambientales

In this work, the design of two specific courses by activities with the objective of developing generic competences by students is presented. Among these, oral and written communication and specific competences of Environmental Parasitology and Environmental Organic Chemistry are considered. All this has been done in the new objectives and requirements of the European Higher Education Area (EHEA). In this context, the EHEA proposes to support the personal development of the students to make them competent in their future professional careers and in their life as active citizens. This paper presents the experience of several years of work with students of Environmental Sciences at the University of Almeria (Spain). The main conclusion is that working generic competences require reducing the theoretical contents of the courses, although the new design has allowed student to get more interested an involved in the courses, and to get competences that did not have before.

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].