Stereoselective three-step one-pot cascade combining Amino- and Biocatalysis to access Chiral y-Nitro Alcohols

he combination of small-molecule catalysis and enzyme catalysis represents an underexploited area of research with huge potential in asymmetric synthetic chemistry due to both compatibility of reaction conditions and complementary reactivity. Herein, we describe the telescopic synthesis of chiral nitro alcohols starting from commercially available benzaldehyde derivatives through the one-pot three-step chemoenzymatic cascade combination of a Wittig reaction, chiral-thiourea-catalysed asymmetric conjugate addition, and ketoreductase-mediated reduction to access the corresponding target compounds in moderate to excellent overall isolated yields (36–80 %) and high diastereomeric and enantiomeric ratios (up to >97 : 3). This represents the first example of the combination of an organocatalysed asymmetric conjugate addition via iminium ion activation and a bioreduction step catalysed by ketoreductases

Construction of chemoenzymatic linear cascades for the synthesis of chiral compounds

Inspired by nature, synthetic chemists try to mimic the efficient metabolic networks in living organisms to build complex molecules by combining different types of catalysts in the same reaction vessel. These multistep cascade processes provide many advantages to synthetic procedures, resulting in higher productivities with lower waste generation and cost. However, combining different chemo- and biocatalysts can be challenging as reaction conditions might differ greatly. As a highly multidisciplinary field that benefits from advances in chemical catalysis, molecular biology and reaction engineering, this area of study is rapidly progressing. In this Review, we highlight recent trends and advances in the construction of multistep chemoenzymatic one-pot cascades to access chiral compounds as well as the different strategies to solve current challenges in the field.We would like to thank the Agencia Estatal de Investigación for financial support (PID2020-113351RA-100/AEI/10.13039/ 501100011033), and the Research Group E07_20R for scientific support. J.M-S also thanks the ARAID Foundation for personal funding.Peer reviewe

Cascade processes merging chemical and enzyme catalysis

Cascade processes are an attractive strategy to rapidly build molecular complexity and circumvent the need to isolate reaction intermediates, providing higher efficiencies into synthetic routes with lower environmental toll. We have recently developed a new method to synthesise chiral 1,4-nitro alcohols by sequentially combining three transformations in the same reaction vessel via asymmetric C–C bond formation using a chiral thiourea catalyst and a bioreduction process as key steps.We would like to thank the Agencia Estatal de Investigación (AEI), the Ministerio de Ciencia e Innovación (Ministry of Science and Innovation, MCIN), and the EU for the financial support (PID2020-113351RA-100/AEI/10.13039/501100011033 and TED2021-130803B-I00 MCIN/AEI /10.13039/501100011033 NextGenerationEU/PRTR). J.M-S also thanks the Fundación Agencia Aragonesa para la Investigación y el Desarrollo (Aragonese Foundation for Research & Development, ARAID) for personal funding.Peer reviewe

Chemoenzymatic one-pot cascade for the construction of asymmetric C-C and C-P bonds via formal C-H activation

The integration of organocatalysis and enzyme catalysis in one-pot cascade processes allows for the efficient construction of complex molecular architectures with high levels of stereocontrol. However, challenges related to reaction compatibility between both processes are often a limitation for the development of efficient synthetic routes. In this study, we describe the combination of an enzymatic aerobic oxidation followed by the squaramide-mediated asymmetric formation of C-P and C-C bonds to access important building blocks such as chiral α-hydroxy phosphonates and β-nitro alcohols in good yields and enantiomeric ratios. This sequential process is conducted in a one-pot fashion within a biphasic system and represents a pioneering example of a chemoenzymatic cascade involving aerobic biooxidation and an organocatalytic step operating under hydrogen-bond activation mode

Combinación de procesos bio y organocatalíticos para la generación de nuevos enlaces C-C

Resumen del póster presentado a la 9ª Jornada de Jóvenes Investigadores de Química y Física de Aragón, celebrada el 16 de diciembre de 2021 en la Universidad de Zaragoza.Peer reviewe

Viscosidad y conductividad eléctrica en dispersiones de arcillas de las cuencas mineras turolenses

2 figuras.-- Resumen del póster presentado en la XV Reunión del Grupo Español del Carbón, 24-27 abril 2022, Granada (España).-- C-27.-- D.L. GR 695-2022Las cuencas carboníferas, que han sido tan explotadas hasta nuestros días, suelen ser también depósitos de arcillas de notable calidad para la elaboración de cerámica plana (gres), sanitarios, porcelana y, recientemente, nanomateriales de tipo 2D. La explotación de esos depósitos de arcilla puede contribuir a la reconversión de las cuencas mineras, como es el caso de la comarca del mismo nombre, en la provincia de Teruel. El procesado de las arcillas implica frecuentemente la preparación de dispersiones o coloides mediante la adición de defloculantes. Sin embargo, el control de calidad de tales suspensiones coloidales es complejo debido a que se trata de sistemas fuera del equilibrio. Así, sus propiedades, además de depender de los parámetros habituales de composición, temperatura, etc., evolucionan lentamente con el tiempo, lo que dificulta encontrar puntos de referencia en los que realizar medidas reproducibles. En esta comunicación se presentan medidas de viscosidad y conductividad electrolítica en suspensiones concentradas de dos arcillas. Se presta especial atención a la evolución de dichas magnitudes con el tiempo y frente a varias adiciones de silicato de sodio como defloculante.Proyecto financiado por el Gobierno de Aragón (Grupo Reconocido T03-20R). Se agradece la colaboración de la Universidad de Zaragoza a través de Universa.Peer reviewe