Total synthesis of (.+-.)-breynolide, an aglycon derivative of the orally active hypocholesterolemic agent breynin A

The total synthesis of (±)-breynolide (3), an aglycon derivative of the potent, orally active hypocholesterolemic glycoside breynin A, has been achieved via a stereochemically linear strategy. The successful approach entailed union of the anion derived from 58 with aldehyde 54 followed by an anomerically driven spiroketalization-equilibration protocol