Current Organic Chemistry - Volume 22, Issue 21, 2018

This paper presents an overview of known experimental data dealing with the mirror symmetry breaking effect in stochastic reactions (crystallization of NaClO3 from an oversaturated aqueous solution; dissolution-crystallization of the l- and d-NaClO3 crystals mixture under stirring or boiling (Viedma ripening), and similar reactions; Soai reaction of enantioselective autocatalysis and chirality amplification; spontaneous mirror symmetry breaking by molecular self-assembly of achiral molecules and similar reactions in polymerization or liquid crystal media). Stochastic effects of chiral or racemic fields and the effect of chiral memory are discussed as well. P. Curie was convinced that “without asymmetric physical impact no asymmetric chiral effect arises”. Recent experimental data that proves the implementation of this criterion is discussed. The aforesaid reactions or effects are considered in terms of a possible chiral impact of external physical inductors as it can be expected for open systems. The meso-form structure of the environment, plasma torch of meteorite impact as a mirror symmetry breaking factor, solar asymmetric irradiation, enantioselective impact of electromagnetic fields (as a combination of the Earth magnetic field and atmospheric electricity), and some other physical inductors are reviewed. The meso-form structure of the gravitational field as a chiral inductor is most consistent with the above– mentioned reactions and effects.

1,3-Dicarbonyls are widely used in organic reactions. They are able to perform as precursors of pyrimidinones, pyrroles, quinolones, isoquinolines, triazoles and furans et al. Their great success is rooted in the fact that most 1,3-dicarbonyls are commercial (or easy to prepare), stable and versatile. This review will focus mainly on three kinds of reactivity patterns, broadly known as radical, nucleophilic and electrophilic, and will not consider the asymmetric synthesis. Reactions of 1,3-dicarbonyls with carbocations, aldehydes, ketones, imines, alkenes, arynes, halogen reagents, thiol reagents, amines, azides, phenols, isocyanides and organometallic reagents will be discussed briefly. The collection of references for the present review was from January 1, 2007, and till June 26, 2018. We hope the decennary advances will help our future research in this area.

Many biologically active compounds possess 1-sulfonyl pyrrolidine structural motif. Therefore, the development of facile methods for the preparation of these compounds in optically pure form is relevant. One of the regio- and stereoselective approaches to the pyrrolidine derivatives is cycloaddition. Thus, this review article is an attempt to survey literature describing synthetic methods for the preparation of 1-sulfonyl pyrrolidine derivatives via various cycloaddition reactions.

With the increasing application and further research of polysaccharides, the development of new green techniques arouses wide attention from academia and industry. Due to special physicochemical properties, ionic liquids (ILs) have been applied widely in carbohydrate chemistry mainly as green and efficient chemical solvents/catalysts for the degradation, synthesis and modification of polysaccharides. Their roles and potential should be fully understood by researchers in carbohydrate chemistry. Because of their unique characters different from other traditional reagents, it is necessary to explore and review the uses, performance, advantages and disadvantages of ILs in detail. This paper focuses on the new advances in the application of ILs to the degradation of cellulose together with the synthesis and modification of polysaccharide; those important findings and systematic comparison were also introduced. Finally, the key conclusions were provided for related researchers and their future was analyzed, and this review was supposed to be a useful reference in the cross-subject area of glycochemistry and green chemistry.

Titanium tetrachloride has been successfully used in the benzylation of aromatic substrates with a series of benzyl alcohols under mild reaction conditions. With monosubstituted aromatic substrates, ortho and para-substituted products are obtained in almost comparable amounts. With sterically hindered benzyl alcohol derivatives almost exclusively para-substitution occurs.