The stereocontrolled total synthesis of altohyrtin A/spongistatin 1: the southern hemisphere EF segment.


The fully functionalized C29-C51 southern hemisphere I·I- of altohyrtin A/spongistatin 1, incorporating the E- and F-ring tetrahydropyran rings and the unsatd. side chain, has been synthesized in a highly convergent and stereocontrolled manner. Key steps in the synthesis of this phosphonium salt include four highly diastereoselective, substrate-controlled, boron aldol reactions to establish key C-C bonds and accompanying stereocenters, where the introduction of the chlorodiene side chain and the C47 hydroxyl-bearing center were realized by exploiting remote stereoinduction from the F-ring tetrahydropyran.

Organic & Biomolecular Chemistry