Eduardo Rodrigo

Electrifying Organic Synthesis

Abstract The direct synthetic organic use of electricity is currently experiencing a renaissance. More synthetically oriented laboratories working in this area are exploiting both novel and more traditional concepts, paving the way to broader applications of this niche technology. As only electrons serve as reagents, the generation of reagent waste is efficiently avoided. Moreover, stoichiometric reagents can be regenerated and allow a transformation to be conducted in an electrocatalytic fashion. However, the application of electroorganic transformations is more than minimizing the waste footprint, it rather gives rise to inherently safe processes, reduces the number of steps of many syntheses, allows for milder reaction conditions, provides alternative means to access desired structural entities, and creates intellectual property (IP) space. When the electricity originates from renewable resources, this surplus might be directly employed as a terminal oxidizing or reducing agent, providing an ultra‐sustainable and therefore highly attractive technique. This Review surveys recent developments in electrochemical synthesis that will influence the future of this area.

Modern Electrochemical Aspects for the Synthesis of Value‐Added Organic Products

Abstract The use of electricity instead of stoichiometric amounts of oxidizers or reducing agents in synthesis is very appealing for economic and ecological reasons, and represents a major driving force for research efforts in this area. To use electron transfer at the electrode for a successful transformation in organic synthesis, the intermediate radical (cation/anion) has to be stabilized. Its combination with other approaches in organic chemistry or concepts of contemporary synthesis allows the establishment of powerful synthetic methods. The aim in the 21st Century will be to use as little fossil carbon as possible and, for this reason, the use of renewable sources is becoming increasingly important. The direct conversion of renewables, which have previously mainly been incinerated, is of increasing interest. This Review surveys many of the recent seminal important developments which will determine the future of this dynamic emerging field.

Nitrophenylacetonitriles as versatile nucleophiles in enantioselective organocatalytic conjugate additions.

Arylacetonitriles are able to participate in organocatalytic Michael additions to alpha,beta-unsaturated aldehydes by incorporating a nitro group at the phenyl ring, which acts as a temporary activating group in a remote position and allows further transformations. The sequential protocol Michael addition/NaBH(4) reduction/lactonization allows the synthesis of diastereomerically pure disubstituted lactones in high yield and optical purity.

Organocatalytic Michael addition/intramolecular Julia-Kocienski olefination for the preparation of nitrocyclohexenes.

An asymmetric organocatalytic [3 + 3] annulation strategy based on a Michael addition/intramolecular Julia-Kocienski olefination sequence has been developed for the synthesis of 4-substituted-5-nitrocyclohex-1-ene compounds. The strategy is an alternative to the direct reluctant enantioselective Diels-Alder approach. The potential of the methodology has been demonstrated with a concise enantioselective formal synthesis of trandolapril.

Unexpected reactivity of graphene oxide with DBU and DMF

An unusual reaction between GO, DBU and DMF, that typically uses base and solvent, has been thoroughly analyzed providing valuable basic knowledge about the reactivity of GO, which is essential to control functionalization and therefore the properties of graphene derivatives. A combination of characterization techniques, experiments and theoretical calculations allowed us to propose a structure for the materials and a plausible mechanism. The catalytic activity of the new basic materials was also analyzed.

A Protocol To Transform Sulfones into Nitrones and Aldehydes

A simple method to transform sulfones into nitrones and therefore into the corresponding carbonyl derivatives has been developed. Some examples demonstrate that it is a new reliable and versatile reaction in the toolbox of sulfones that has great synthetic potential. NMR and computational studies were used to elucidate the mechanism.

A very simple one-pot electrosynthesis of nitrones starting from nitro and aldehyde components

The cathodic treatment of nitroarenes in the presence of aldehydes yields directly and selectively nitrones. Electrolysis can be conducted on a very simple undivided beaker-type cell under constant current conditions. The conversion tolerates multiple bonds, a variety of functional groups and heterocyclic moieties. Competing reductive conversions such as pinacolization are not observed. The green aspects of this electro-conversion are avoidance of metals, an environmentally benign solvent mixture, and stable as well as sustainable carbon electrodes.