Formal total synthesis of erythromycin A. Part II. Preparation of a 1,7-dioxaspiro[5.5]undecane derivative of erythronolide A seco acid methyl ester from erythromycin A

Abstract

Degradation of erythromycin A gives spirocompound 18A. Compound 18A is then converted into the spirolactone 22 via 21. Compound 21 is then reconverted into spiro product 18A.