Bis(indole) alkaloids from Arundo donax were synthesized using the first ynindole Diels-Alder reaction. The alkaloids are chiral, having stable enantiomeric conformations with half-lives of racemization of t1/2 = 4150-25100 seconds at room temperature. Their absolute stereochemistry was determined using the exciton chirality method.

The enantioselective α-vinylation of aldehydes using vinyl iodonium triflate salts has been accomplished via the synergistic combination of copper and chiral amine catalysis. These mild catalytic conditions provide a direct route for the enantioselective construction of enolizable α-formyl vinylic stereocenters without racemization or olefin transposition. These high-value coupling adducts are ...

Total synthesis of cryptocin, a fungus metabolite, was achieved based on the biosynthetic hypothesis. A variety of derivatives of cryptocin, equisetin and fusarisetin A were prepared, wherein the racemization of C-3 and diastereoselectivity of C-5 were investigated. We further examined their inhibitory effects on breast cancer cell survival and metastasis, and summarized the structure-activity ...

An efficient stereocontrolled preparation of chiral phenanthroindolizidines is detailed. The synthesis relies on the stereoselective indium-mediated allylation of 2-(phenanthren-9-yl)acetaldehyde derivatives with chiral tert-butylsulfinamide. Chemoselective transformations from the corresponding homoallylic sulfinamine allow the synthesis of the phenanthroindolizidines in only three synthetic o...

Divergent evolution of enzyme function is commonly explained by a gene duplication event followed by mutational changes that allow the protein encoded by the copy to acquire a new function. An alternate hypothesis is that this process is facilitated when the progenitor enzyme acquires a second function while maintaining the original activity. This phenomenon has been suggested to occur in the o...

The first documented study of the borono-Mannich (Petasis) reactions of pinacol allenylboronate is described. The reactions of salicylaldehyde and primary and secondary amines are highly regioselective and give homopropargylamine and α-allenylamine products, respectively. In contrast, glycoaldehyde and chiral α-hydroxyaldehydes give exclusively anti-β-amino-β-allenyl alcohol products, irrespect...

Circular dichroism (CD) spectroelectrochemistry is used to determine the extent of singly occupied molecular orbital delocalization in mixed-valence multinuclear complexes, specifically the mixed-valence Ru(II)Ru(III) states of the four diastereoisomers of [(Ru(bpy)(2))(2)(bpt)](3+) [1; bpy = 2,2'-bipyridyl and bpt = 3,5-bis(pyrid-2'-yl)-1,2,4-triazolato anion]. The complex was found to be stab...

N-Acylsulfonamide derivatives have important applications in organic synthesis and drug discovery. It was found that many problems occurred preparing amino acid derived N-acylsulfonamides with the commonly used coupling approach in our previous studies. In this paper, we report an efficient approach to synthesize various amino acids derived N-acylsulfonamides in high yields without any racemiza...

This paper describes a simple, cost-effective and one pot process for racemization of undesired (S)-3-(carbamoylmethyl)-5-methylhexanoic acid, which produced during the resolution step. The unwanted S-enantiomer was converted into the symmetrical glutarimide derivative in the presence of a catalytic amount of DMAP or pyridine in refluxing toluene followed by hydrolysis with an alkali.