Kinetic control in noncovalent synthesis: regioselective ligand exchange into a hydrogen bonded assembly

This paper illustrates the use of a kinetically controlled exchange reaction to effect regioselective modification of a hydrogen-bonded assembly. Both the bound anion and cation can control the exchange of ligand into the different layers of a synthetic G-quadruplex.     

Kiliani reactions on ketoses: branched carbohydrate building blocks from D-tagatose and D-psicose

D-Tagatose and D-psicose on treatment with sodium cyanide gave mixtures of branched sugar lactones; extraction of the crude products by acetone in the presence of acid permits direct access to branched carbohydrate diacetonides, likely to be of value as new chirons. In both cases, the major lactone products—diacetonides with a 2,3-cis-diol relationship—can be crystallised in around 40-50% yield from the ketohexose. A practical procedure for the conversion of 30 g of D-tagatose to give 24 g of 2,3:5,6-di-O-isopropylidene-2-C-hydroxymethyl-D-talono-1,4-lactone is reported.     

Crystallographic characterization and structural analysis of the first organic functionalization product of the endohedral fullerene Sc(3)N@C(80)

The structure of Sc3N@C80-C10H12O2, a Diels-Alder cycloadduct of Sc3N@C80, has been determined. The crystallographic data shows that cycloaddition occurs at a C-C bond of 6:5 ring junction, and that the fullerene C1-C2 bond is elongated and pulled out from the fullerene. The Sc3N unit is well-ordered within the C80 cage and positioned away from the site of addition. The proximity of the Sc atoms to the cage carbon atoms causes those carbon atoms to protrude slightly from the surface of the fullerene cage.