This microreview summarizes the use of deep eutectic solvents (DES) and related melts in Organic Synthesis. This type of solvents combine the great advantages of other proposed environmentally benign alternative solvents, such as low toxicity, high availability, low inflammability, high recyclability, low volatility and low price, avoiding many disadvantages of these neoteric media. The fact that many of the components of the mixture come directly from Nature assures their biodegradability and renewability. The classification and distribution of the reactions in different sections along this microreview, as well as the emphasis paid to their scope, easily allows a general reader to understand the actual state of art, and the great opportunities opened, not only for academic proposes but also for industry.

Complex [Os(η 6 -p-cymene)(OH)(IPr)]OTf is an efficient catalyst precursor for the α-alkylation of arylacetonitriles and methyl ketones with alcohols, which works with turnover frequencies between 675 and 176 h −1 for nitriles and between 194 and 28 h −1 for ketones.

The asymmetric conjugate addition of carbon and heteroatom nucleophiles to nitroalkenes is a very interesting tool for the construction of highly functionalized synthetic building blocks. Thanks to the rapid development of asymmetric organocatalysis, significant progress has been made during the last years in achieving efficiently this process, concerning chiral organocatalysts, substrates and reaction conditions. This review surveys the advances in asymmetric organocatalytic conjugate addition reactions to α,β-unsaturated nitroalkenes developed between 2013 and early 2017.

In the Minireview by Alonso, Pastor et. al., the wrong journal was cited in reference [18a], the correct reference is included below. We apologize for this oversight.

b S Supporting Information' INTRODUCTION N-heterocyclic carbenes (NHCs) are cyclic "Fischer-type" ligands bearing at least one R-amino substituent. 1 During the past few years, their chemistry has experienced explosive development, due to the design of diverse homogeneous catalytic systems comprising such carbene ligands 2 and use of NHC complexes as antimicrobial and cytotoxic agents, 3 as photoactive sites in luminescent materials for self-assembly into liquid crystalline materials and metallosupramolecular structures, and as synthons for molecular switches and conducting polymeric materials. 4 The vast majority of reported NHC ligands are substituted at nitrogen(s) by alkyl or aryl groups. Deprotonation of imidazolium salts and transmetalation from silver are the most used synthetic pathways for the preparation of complexes containing these ligands. 5 However, the cleanest synthetic strategy is undoubtedly direct metalation. This method requires the presence at the starting complex of strong Brønsted bases, which afford labile Brønsted acid ligands as a result of the deprotonation of the imidazolium salt. Unfortunately, the basic precursors are limited to [M(μ-OMe)(diolefin)] 2 (M = Rh, Ir) 6 and M(OAc) 2 (M = Ni, 7 Pd, 8 Pt 9 ). Recent reports have shown that these compounds can undergo transformations via a range of NHC reactions, 10 including migratory insertion, 11 N-substituent cleavage, 12 ring expansion involving heterocyclic N-C bond cleavage, 13 and C-H 14 and C-C 15 bond activation of the N-alkyl or N-aryl substituents.Imidazolium salts with carbonyl, 16 pyridyl, 16a,17 pyrazolyl, 18 amine, 19 and phosphine 20 substituents are also known. They can be deprotonated and are thus suitable for the preparation of metal complexes. Alcohol-functionalized imidazolium salts are readily accessible by the nucleophilic opening of epoxides. 21 The alcohol function appears to be more acidic than the heterocycle. A single deprotonation leads to a zwitterionic alcoholate ABSTRACT: The hexahydride complex OsH 6 (P i Pr 3 ) 2 (1) reacts with 1-mesitylimidazole, 1-methylimidazole, 1-(2-hydroxy-2-phenylethyl)imidazole, and 1-(2-hydroxypropyl)imidazole to give the N-bound imidazole compounds OsH 4 -(RIm)(P i Pr 3 ) 2 (R = Mes (2), Me (3), CH 2 CH(OH)Ph (4), CH 2 CH(OH)CH 3 (5)) and H 2 . In toluene under reflux the alcohol derivatives 4 and 5 evolve into the C-bound imidazole complexes À