Fostering research in fundamental organic transformations is of utmost importance for the development of science. Catalysts based on transition metals are generally costly and contaminating. There are applications where even the tiniest amount of a heavy metal is not tolerated in the end product of an organic synthesis. The pharmaceutical industry may be one of the most representative cases of this situation. Therefore, the search for environmentally benign catalysts capable of increasing the rates of carbon-carbon and carbon-heteroatom bond formation under metal-free conditions becomes a hot research topic in fundamental organic chemistry. An increase in this know-how will stimulate new practical applications of relevant findings. This issue contains one review, three articles and two communications. The review article by Pierre Vogel, Yu-hong Lam, Adam Simon, and Kendall N. Houk [1] discusses the applications of several organocatalysts. It is organized according to the mechanism of the reactions that they catalyze rather than by the identity of the catalyst. It focusses on four classes or fundamental organic reactions: acyl group transfers (esterification and ester hydrolysis, acid or base-catalyzed acyl transfers, use of amphoteric compounds as catalysts for acyl transfers, catalysis by nucleofugal group substitution, N-heterocyclic carbene-catalyzed transesterifications, enzyme-catalyzed acyl transfers, mimics of carbopeptidase-A, direct amide bond formation from amines and carboxylic acids), nucleophilic additions to the carbonyl group (nucleophilic additions to aldehydes, ketones and imines, bifunctional catalysts for nucleophilic addition/elimination, σand π-nucleophiles as catalysts for nucleophilic additions to aldehydes and ketones, self-assembled encapsulation, catalysis of conjugate additions), anionic nucleophilic displacement reactions (reactions in the gas phase, pulling on the leaving group, phase transfer catalysis, asymmetric ion-pairing catalysis), and CC bond-forming reactions involving umpolung (umpolung of aldehydes-benzoin condensation, Stetter reaction-, umpolung of enals, umpolung of Michael acceptors, the Rauhut-Currier reaction, the Morita-Baylis-Hillman reaction, nucleophilic catalysis of cycloadditions). It shows how the knowledge of the reaction mechanisms has led to the invention of homogenous molecular catalysts for the most important organic reactions. In summary, a tutorial on metal-free catalysis in only 65 pages! The reactions of boronic acids and their derivatives under metal-free conditions constitute a new rapidly expanding field of organoboron chemistry. Yuri Bolshan et al. [2] present herein a new CC bond-forming reaction of potassium trifluoroborates. They have discovered that in the presence of a Brønsted acid (HBF 4), potassium alkenyl-and alkynyltrifluoroborates react with oxocarbenium ions generated from cyclic acetals to form ethers. Zhen Li, Jing Chen et al. [3] have used pyrrolidine and its derivatives, pyrrolidine-3-amine in particular, to catalyze aldol and Knoev...
