Synthesis of γ-, δ-, and ε-Lactams by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)iminoesters

Highly enantiomerically enriched γ- and δ-lactams have been prepared by a simple and very efficient procedure that involves the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)iminoesters followed by desulfinylation of the nitrogen atom and spontaneous cyclization to the desired lactams during the basic workup procedure. Five- and six-membered ring lactams bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and ee’s up to >99%. A slight modification of the procedure also allowed the preparation of ε-lactams in good yields and very high enantioselectivities. Both enantiomers of the final lactams could be prepared with equal efficiency by changing the absolute configuration of the sulfinyl chiral auxiliary.

Cambios en la estructura metropolitana durante la última década. El caso del Área Metropolitana de Valencia

La realidad metropolitana de los países desarrollados está experimentando cambios importantes asociados a la creciente separación entre los espacios de residencia y trabajo. En las áreas metropolitanas se dan los procesos de este tipo más complejos cuyas consecuencias territoriales inmediatas son la potenciación de ciertas centralidades a la vez que crecen centros nuevos o tradicionales en sus áreas de influencia. La estructura territorial (la red urbana y de transportes, fundamentalmente) en el Área Metropolitana de Valencia (AMV) incide claramente en los problemas asociados a la equidad social y a la sostenibilidad ambiental. La comunicación que aquí se presenta se centra en el análisis de dichos cambios en la última década, a partir del comportamiento demográfico de los municipios, las pautas generales de movilidad y los cambios en la ocupación del suelo en el AMV.

Life-cycle portfolio choice with liquid and illiquid financial assets

Traditionally, quantitative models that have studied households׳ portfolio choices have focused exclusively on the different risk properties of alternative financial assets. We introduce differences in liquidity across assets in the standard life-cycle model of portfolio choice. More precisely, in our model, stocks are subject to transaction costs, as considered in recent macroliterature. We show that when these costs are calibrated to match the observed infrequency of households׳ trading, the model is able to generate patterns of portfolio stock allocation over age and wealth that are constant or moderately increasing, thus more in line with the existing empirical evidence.