New anti-HIV derivatives: synthesis and antiviral evaluation

Acylsulfonamide safety-catch linker: promise and limitations for solid-phase oligosaccharide synthesis

Safety-catch linkers are useful for solid-phase oligosaccharide synthesis as they are orthogonal to many common protective groups. A new acylsulfonamide safety-catch linker was designed, synthesized and employed during glycosylations using an automated carbohydrate synthesizer. The analysis of the cleavage products revealed shortcomings for oligosaccharide synthesis.

Seebach's conjunctive reagent enables double cyclizations

When ketones flanked on both sides by nucleophilic atoms react with Seebach's nitropropenyl pivaloate reagent, direct couplings take place to give two new ring systems and three bonds. Cis-ring fusions are observed in unions leading to 5,5-, 5,6-, and 6,6-bicycles. Densely functionalized and rigid frameworks may be rapidly formed by the chemistry described herein.