Chemoselective removal and replacement of the C-4′ and C-6 acyl esters of zaragozic Acid A

An efficient chemical sequence is described for the modification of the C-4' and C-6 positions of zaragozic acid A. Key reactions include the specific conditions devised for selective removal of either the C-4' acetate or the C-6 acyl chain. The resultant hydroxy intermediates were then derivatized as esters, ethers, carbamates, and carbonates.