Efficient syntheses of the coumarins, nordentatin, dentatin and clausarin

Article abstract of DOI:10.1016/S0040-4039(00)94531-3

A convenient synthetic route to the linear pyranocoumarins, nordentatin (5) and dentatin (6), has been established. A novel out-of-ring Claisen rearrangement has been employed in the synthesis of clausarin (10). The structure of clausenidinaric acid has been reassigned as 11.