Enynone dihydroxylation-cyclisation as a route to densely functionalised 3(2H)-furanone derivatives: an approach to the core of the zaragozic acids

The synthesis of an advanced intermediate is described that could secure the polyoxygenated core of zaragozic acids and related natural products. The key strategy employs a two-step synthesis of the 3(2H)-furanone ring system by catalytic dihydroxylation-mercury(II)/acid-catalysed cyclisation with concomitant deprotection. The scope of the 3(2H)-furanone synthesis has been evaluated, and this ring system is shown to remain intact in multi-step reaction sequences. Access to novel, highly oxygenated 3(2H)-furanone derivatives has been achieved.