Current Organic Chemistry - Volume 16, Issue 15, 2012

3,3'-disubstituted axially dissymmetric BINOLS, owing to their lower acidity have limited organocatalytic applications in stereoselective transformations. Nevertheless, they serve as potent and immediate precursors to much stronger Bronsted acids e.g. binaphthyl phosphoric acids. The review lists some suitably substituted and sterically demanding BINOLS, their use in organic transformations and possibility to convert them into stronger Bronsted acids as more effective organocatalysts.

Nitrogen-containing heterocycles, and more specifically the chiral ones, possess various biological and pharmaceutical properties. Among the approaches to these compounds, the organocatalyzed asymmetric multicomponent reaction has emerged as a powerful tool. This review will focus on the later development to chiral dihydropyridines, dihydropyrimidines and quinolizidines via asymmetric organocatalyzed synthesis....

In this review, we have focused our attention on the application of dendrimers as asymmetric catalyst in organic synthesis, which appeared in the literature. Dendrimers have been identified as a promising candidate for catalysis application. The combination of high surface area and high solubility makes dendrimers as useful nanoscale catalysts. The main advantage of the dendritic catalysts is they can be separated from the reaction mixture by simple solvent precipitation and reused for several times with similar catalytic activity. Importance of catalytically active substances like metal salts or organic molecule like pyrrolidinylmethanol thatare attached either to the core or to the periphery of the dendrimers have been highlighted and their applications in important organic reactions such as Baylishillman, Mannich-type, Diels-Alder, Wittig reaction, Michael addition, addition of dialkylzinc to aldehyde, asymmetric epoxide ring opening, asymmetric hydrogenation and asymmetric epoxidation are also presented. Use of dendrimer based salts and chiral compounds in asymmetric syntheses are discussed and the advantages and disadvantages of those catalysts are brought out in this review.

This review is devoted to the design of new salen type ligands and its applications in the asymmetric catalysis. The main achievements in this field include development of recyclable catalysts, investigation of the mechanism of the secondary alcohols oxidative resolution and the asymmetric Henry reaction, and a study of the synthetic advantages of the salen complex catalysis. The aim of this review is to present an overview of the literature on the recent progress in the salen ligand catalytic chemistry.

The catalysis by dirhodium paddlewheel complexes has been an area of immense interest and extensive study over the past three decades - not only because most of the catalysts are highly stable to heat, moisture and ambient atmosphere but also for the asymmetric induction in the ylide generation. In this review, we attempt to provide an overview on the general preparation method for most homogeneous chiral dirhodium(II) catalysts that have appeared to date and their recent applications in asymmetric catalysis with iodonium ylides as carbenoid precursors.