Facile Coupling of Aldehydes with Alcohols: An Evolved Tishchenko Process for the Preparation of Unsymmetrical Esters

Recent developments in highly basic N-heterocyclic iminato ligands in actinide chemistry

In the last decade, major conceptual advances in the chemistry of actinide molecules and materials have been made to demonstrate their distinct reactivity profiles as compared to lanthanide and transition metal compounds, but some difficult questions remain concerning the intriguing stability of low-valent actinide complexes, and the importance of the 5f-orbitals in reactivity and bonding. The imidazolin-2-iminato moiety has been extensively used in ligands for the advancement of actinide chemistry owing to its unique capability of stabilizing the reactive and highly electrophilic metal ions by virtue of its strong electron donation and steric tunability. The current review article describes recent developments in the chemistry of light actinide metal ions (thorium and uranium) bearing these N-heterocyclic iminato moieties as supporting ligands. In addition, the effect of ring expansion of the N-heterocycle on the catalytic aptitude of the organoactinides is also described herein. The synthesis and reactivity of actinide complexes bearing N-heterocyclic iminato ligands are presented, and promising apposite applications are also presented. The current review focuses on addressing the catalytic behavior of actinide complexes with oxygen-containing substrates such as in the Tishchenko reaction, hydroelementation processes, and polymerization reactions. Actinide complexes have also found new catalytic applications, as demonstrated by the potent chemoselective carbonyl hydroboration and tandem proton-transfer esterification (TPTE) reaction, featuring coupling between an aldehyde and alcohol.

Electro-Oxidative Selective Esterification of Methylarenes and Benzaldehydes

A mild and green electro-oxidative protocol to construct aromatic esters from methylarenes and alcohols is herein reported. Importantly, the reaction is free of metals, chemical oxidants, bases, acids, and operates at room temperature. Moreover, the design of the electrolyte was found critical for the oxidation state and structure of the coupling products, a rarely documented effect. This electro-oxidative coupling process also displays exceptional tolerance of many fragile easily oxidized functional groups such as hydroxy, aldehyde, olefin, alkyne, as well as neighboring benzylic positions. The enantiomeric enrichment of some chiral alcohols is moreover preserved during this electro-oxidative coupling reaction, making it overall a promising synthetic tool.

Efficient synthesis of esters through oxone-catalyzed dehydrogenation of carboxylic acids and alcohols

An environmentally friendly oxone (20 mol%) catalyzed esterification of carboxylic acids with alcohols has been developed, providing an attractive alternative to the construction of valuable carbonyl esters.