Total synthesis of the boron-containing ion carrier antibiotic macrodiolide tartrolon B

The first total synthesis of the boron-containing macrodiolide antibiotic tartrolon B is reported in full detail. Two convergent approaches to the target compound are described, the first of which eventually failed, due to sensitive functionality. In the second, successful route the key step was a stereoselective boron-mediated aldol addition of a bicyclic acetonide protected ketone to a diene-aldehyde. In this case the synthesis could be completed without major problems, using a Yamaguchi dimerization macrolactonization endgame.