Thiophilic ring-opening and rearrangement reactions of epoxyketone natural products.

Thiol additions to the highly functionalized core structures of aranorosin- and manumycin-type antibiotics reveal the general reactivity patterns of epoxyketone natural products. Rapid hemiacetal and hydrate formations decrease the reactivity of the epoxyketone moiety in aqueous media toward the cellular scavenger glutathione, and secondary 1,2-shift, elimination, aromatization and intramolecular aldol reactions provide novel reaction pathways. In a hydrophobic environment, the thiol-capture function of the ketone moiety facilitates electrophilic attack.

Fluorous synthesis: a fluorous-phase strategy for improving separation efficiency in organic synthesis.

Recovery and purification difficulties can limit the yield and utility of otherwise successful organic synthesis strategies. A "fluorous synthesis" approach is outlined in which organic molecules are rendered soluble in fluorocarbon solvents by attachment of a suitable fluorocarbon group. Fluorocarbon solvents are usually immiscible in organic solutions, and fluorous molecules partition out of an organic phase and into a fluorous phase in a standard liquid-liquid extraction. Simple yet substantive separations of organic reaction mixtures are achieved without resorting to chromatography. Because fluorous synthesis combines in many respects the favorable purification features of solid-phase synthesis with the favorable reaction, identification, and analysis features of traditional organic synthesis, it should prove valuable in the automated synthesis of libraries of individual pure organic compounds.