First diastereoselective [3 + 2] cycloaddition reaction of diethyl isocyanomethylphosphonate and maleimides.

Bicyclic α-iminophosphonates were prepared via the first diastereoselective silver catalyzed [3 + 2] cycloaddition reaction of diethyl isocyanomethylphosphonate and diversely N-substituted maleimides. The reduction of the resulting imine by catalytic hydrogenation led to cyclic α-aminophosphonates, which are α-aminoester surrogates. The relative stereochemistry of the adducts was confirmed by X-ray crystallographic analysis of . The diastereoselectivity of the cycloaddition reaction was rationalised by theoretical studies.

First asymmetric cascade reaction catalysed by chiral primary aminoalcohols.

Readily available chiral primary 1,2-aminoalcohols and diamines have been explored as organocatalysts for a domino Michael-aldol reaction. Their application in this organocascade process afforded cyclohexanone A with high levels of reactivity (up to 91% yield) and stereoselectivity (>97 : 3 d.r., up to 93% ee). Depending on the acid cocatalyst different chiral species (cyclic secondary amines vs. acyclic primary amines) might catalyse the process. In order to shed light on the catalytic activation, several experiments were carried out and a detailed possible reaction mechanism is proposed. Theoretical studies support the stereochemical outcome of the process.

Highly stereoselective double (R)-phenylglycinol-induced cyclocondensation reactions of symmetric aryl bis(oxoacids).

The double cyclocondensation of symmetric pyridyl bis(oxoacids) 2b and 3b with (R)-phenylglycinol stereoselectively gave access to bis-phenylglycinol-derived oxazolopyrrolidine 9 and oxazolopiperidone 10, respectively. Application of the stereocontrolled cyclocondensation reaction to phenyl bis-γ-oxoacid 4b provided 11, which was converted to the corresponding enantiopure di(pyrrolidinyl)benzene 22. The absolute configuration of the new stereogenic centers generated in the key cyclocondenstion step was unambiguously established by X-ray crystallographic analysis.

Tumor odontogénico epitelial calcificante en la rama mandibular. Informe de un caso clínico basado en una actualización bibliográfica / Calcifying epithelial odontogenic tumor in the mandibular ramus. A case report based on a literature update

Objetivo: Presentar un caso clínico de un tumor odon- togénico epitelial calcificante (TOEC), así como una revisión de la literatura disponible sobre esta neoplasia para contribuir al análisis del mejor método de tratamiento de la patología. Caso clínico: Se presenta el caso de una paciente mujer de 35 años con un tumor odontogénico epitelial calcifican- te que recibió tratamiento de enucleación quirúrgica con una evolución favorable y seguimiento de 5 años por medio de evaluación clínica y radiológica. La elección terapéutica se basó en el resultado de un análisis exhaustivo de la literatura para determinar el mejor abordaje de la neoplasia (AU)

Aim: To present a clinical case of a calcifying epithelial odontogenic tumor (CEOT), as well as a review of the availa- ble literature on this neoplasia to contribute to the analysis of the best treatment method for the pathology. Clinical case: The case of a 35-year-old patient with a calcifying epithelial odontogenic tumor who received surgical enucleation treatment with a favorable evolution and 5-year follow-up through clinical and radiological evaluation is pre- sented. The therapeutic choice was based on the result of an exhaustive analysis of the literature to determine the best ap- proach to the neoplasia (AU))

Synthesis and applications of highly functionalized 1-halo-3-substituted bicyclo[1.1.1]pentanes.

Bicyclo[1.1.1]pentanes (BCPs) are important bioisosteres of 1,4-disubstituted arenes, tert-butyl and acetylenic groups that can impart physicochemical benefits on drug candidates. Here we describe the synthesis of BCPs bearing carbon and halogen substituents under exceptionally mild reaction conditions, via triethylborane-initiated atom-transfer radical addition ring-opening of tricyclo[1.1.1.01,3]pentane (TCP) with alkyl halides. This chemistry displays broad substrate scope and functional group tolerance, enabling application to BCP analogues of biologically-relevant targets such as peptides, nucleosides, and pharmaceuticals. The BCP halide products can be converted to the parent phenyl/tert-butyl surrogates through triethylborane-promoted dehalogenation, or to other derivatives including carbonyls, alcohols, and heterocycles.

Direct ortho-arylation of ortho-substituted benzoic acids: overriding Pd-catalyzed protodecarboxylation.

ortho-Arylation of ortho-substituted benzoic acids is a challenging process due to the tendency of the reaction products toward Pd-catalyzed protodecarboxylation. A simple method for preventing decarboxylation in sterically hindered benzoic acids is reported. The method described represents a reliable and broadly applicable entry to 2-aryl-6-substituted benzoic acids.