Vladimir A. Azov

Substrate dependent intramolecular Pauson-Khand reaction of carbohydrate exo-methylene derivatives. Unexpected formation of fused “[4.1.0] bicycloheptene - pyranose” tricyclic product

Abstract Attempted Pauson-Khand cyclisation of exo- methylene carbohydrate enynic substrates is described. 3-Exo methylene derivative cyclises to give a normal Pauson-Khand product while cyclisation of a 4-exo methylene analog follows a previously unreported pathway to give fused “[4.1.0] bicycloheptene - pyranose” tricyclic product.

Selective steroid recognition by a partially bridged resorcin[4]arene cavitand

The partially bridged resorcin[4]arene cavitand featuring a cleft-shaped recognition site formed by two anti-quinoxaline bridges and four convergent HO-groups was prepared in three steps and characterised by X-ray crystallography; cavitand was found to be a selective receptor for steroidal substrates in CDCl3, with the best binding observed for steroids with a flat A-ring and two H-bonding sites on rings A and C/D.