Synthesis of the first members of a new class of biologically active bryostatin analogues

The synthesis of a class of synthetic bryostatin analogues with potent growth inhibitory activity against several human cancer cell lines and exhibiting a high affinity for protein kinase C (PKC) is described. The assembly of a modified bryostatin ring system from readily prepared subunits was accomplished by using an esterification-macrotranscetalization method. Of the units tested, acetal 24a showed great growth inhibitory activity and affinity for PKC.