Abstract:
The synthesis of a series of 5,6-monobenzannulated spiroketals is reported. The use of various styrenes in a Kulinkovich reaction with an appropriately functionalized aliphatic ester affords cyclopropanol products which under basic conditions underwent ring opening to form ketone precursors to the spiroketals. Deprotection of the hydroxyl groups and subsequent cyclization afforded monobenzannulated spiroketals related to the core structure of berkelic acid.