Current Organic Chemistry - Volume 19, Issue 22, 2015

In the rapidly developing areas of nanotechnology, nano-scale materials as heterogeneous catalysts in the synthesis of organic molecules have got more and more attentions. In this review, we will summarize the synthesis of a new type of ultrathin nanostructure via wet chemical method and several new catalytic applications to establish heterogeneous catalytic system in “green” environments. Further study shows that these materials have higher catalytic activity and selectivity than previously reported nanocrystal catalysts. This review intends to combine nanomaterials preparation and organic chemistry to find new catalysts for low-cost, efficient, highly selective chemical synthesis. The catalytic transformation of functional groups based on novel nanomaterials, can achieve not only "atoms economy", but also the chemical processes show low energy consumption and induce low pollution at the same time. The whole process might have a great impact to resolve the energy crisis and the environmental crisis, which was caused by the traditional chemical engineering. The main contents of the review include: 1) synthesis of ultrathin metallic nanostructures; 2) important catalytic molecule activation and the functional group transformation process at interface in the nano-catalyzed process; 3) understanding the effect of crystal structure of the nano-catalysts on the catalytic activity; 4) point out a novel solution of "green chemistry" based on non-supported nanocatalyst.

Photochemistry has tremendous applications in the synthetic organic chemistry. The photochemical behaviors of compounds containing carbonyl chromophores are most widely and extensively investigated as these elicit many types of photochemical reactions. Of these, the photochemical intramolecular H-abstraction reactions are of great importance as these have been used as the suitable tools for the creation of the numerous synthetic and natural exotic small to large ring carbo- and hetero-cyclic molecules. Furthermore, these H-abstraction reactions are performed in clean and mild conditions without the involvement of precious and toxic reagents and construct a route for the development of clean and green methods and are thus of immense utilities in the area of synthetic organic chemistry. This article presents a survey of synthetic utilities as well as the functionalization of unactivated carbon offered by the photochemical intramolecular H-abstraction in addition to our own work in the area.

Corey-Fuchs olefination is a two-step reaction, involving the reaction of an aldehyde and tetrabromomethane (CBr4) in the presence of the triphenylphosphine (Ph3P) to synthesize 1,1-dibromoolefins. In the second step, the conversion of the dibromoolefins to alkynes occurred in the presence of n-BuLi as the base. This transformation was first discovered by E. J. Corey and P. L. Fuchs in 1972. Due to the importance of terminal alkynes in the synthetic organic chemistry, the Corey-Fuchs reaction has found many applications in organic transformations; particularly in the total synthesis of several biologically active natural products, often as starting materials.

A purine nucleoside phosphorylase from Aeromonas hydrophila (AhPNP) was found to catalyze the regio- and stereoselective transfer of the ribofuranosyl moiety from 7-methylguanosine iodide (1) to a library of 6- substituted purines, resulting in moderate to high conversions (18-65%) into their ribonucleoside counterparts (26- 34, 36-49). Exploring of substrate recognition by AhPNP with regard to 6-position of purine base provided the necessary information to exploit this biocatalyst for the chemoenzymatic synthesis of nucleoside analogues through a transglycosylation reaction.