Shan-Yong Chen

Enantioselective Gel Collapsing: A New Means of Visual Chiral Sensing

An optically active BINOL-terpyridine based Cu(II) complex (R)-2 was prepared. Sonication of (R)-2 in CHCl(3) led to the formation of a stable gel. The interaction of this gel with chiral amino alcohols was studied. It was found that (S)-phenylglycinol (0.10 equiv) could break the gel network of (R)-2 (3.75% w/v, g/mL) in CHCl(3) to cause gel collapsing but (R)-phenylglycinol (0.10 equiv) could not. Similar enantioselective gel collapsing was also observed with (R)- and (S)-1-amino-2-propanol. This study demonstrates that chiral molecular gels are potentially useful for visual chiral discrimination. Complex (R)-2 in solution also exhibited significant enantioselective fluorescent enhancement in the presence of a variety of amino alcohols.

Direct arylation of arene and N-heteroarenes with diaryliodonium salts without the use of transition metal catalyst.

A novel and simple transition metal-free direct arylation of arene and N-heteroarenes with diaryliodonium salts has been developed. This cross-coupling reaction is promoted only by base and gives the desired products in moderate to good yields.

Iron-mediated direct Suzuki-Miyaura reaction: a new method for the ortho-arylation of pyrrole and pyridine.

The first example of an iron-mediated direct Suzuki-Miyaura reaction between N-heterocyclic compounds and arylboronic acids is described, and both electron-rich and electron-deficient heteroarenes can be successfully used for the coupling reaction.

Sulfonylation of Five-Membered Heterocycles via an SNAr Reaction

An efficient, concise, and transition metal-free synthesis of functionalized sulfonylated five-membered heterocyclic compounds via an S(N)Ar reaction has been developed. Using commercially available sodium sulfinates as sulfonylation reagents, various five-membered heterocyclic sulfones were obtained in good yields.

Copper-Catalyzed Aerobic Synthesis of 2-Arylpyridines from Acetophenones and 1,3-Diaminopropane

A copper-catalyzed reaction providing direct access to 2-arylpyridines from acetophenones and 1,3-diaminopropane is described. A range of electronically diverse acetophenones undergo this transformation, affording 2-arylpyridines in good yields.

Metal-free alkynylation of α-C–H bonds of ethers with ethynylbenziodoxolones

A metal-free direct alkylation of C–H bonds adjacent to an oxygen or nitrogen atom was developed. This reaction occurred between saturated heterocycles and ethynylbenziodoxolones under mild conditions. A series of 2-alkynyl cyclic alkanes that contain oxygen or nitrogen atoms were prepared in moderate to good yields.

Self-activating chemical nuclease: ferrocenyl cyclen Cu(II) complexes act as efficient DNA cleavage reagents in the absence of reductant.

The interactions of cyclen Cu(II) complexes functionalized by ferrocenyl group with plasmid DNA indicated that these complexes have high cleavage efficiency via an oxidative mechanism in the absence of any reductant or oxidant.

Iodide-catalyzed amide synthesis from alcohols and amines

An efficient method to prepare amides by a cascade strategy was developed. Using nBu4NI or NaI as the catalyst and tert-butyl hydroperoxide as the oxidant, various alcohols reacted with N-hydroxysuccinimide or N-hydroxyphthalimide affording corresponding active esters in moderate to good yield. The resulting active esters were converted into amides smoothly in one pot.

Hydrolytic cleavage of DNA by urea-bridged macrocyclic polyamines

Novel bis-cyclen derivative A with urea, mono-cyclen derivative B with urea and amino acid urea C were synthesized as DNA cleavage agents. The structures of these new compounds were identified by MS and (1)H NMR spectroscopy. The catalytic activities on DNA cleavage of these compounds were subsequently studied, and results show that A is a much better catalyst in DNA cleavage process than that of B and C. The effects of reaction time and catalyst concentration were also investigated. The results indicate that A can catalyze the cleavage of supercoiled DNA (pUC 19 plasmid DNA) to nicked DNA under physiological conditions with high yields (nearly 100%) via a hydrolytic mechanism.

A catalyst-free approach to 3-thiocyanato-4H-chromen-4-ones

A facile and efficient approach to 3-thiocyanato-4H-chromen-4-ones was realized at room temperature. In the presence of KSCN and K2S2O8, various enaminones underwent thiocyanation and cyclization, affording 3-thiocyanatochromenones in good yields. In addition, one-pot synthesis of 3-thiocyanatochromenones from 2-hydroxylacetophenones was also developed.