Conjugate Addition to Acylketene Acetals Derived from 1,8-Dihydroxynaphthalene and Its Application to Synthesize the Proposed Structure of Spiropreussione A

A conjugate addition of diverse nucleophiles to acylketene acetals derived from 1,8-dihydroxynaphthalene (DHN) is developed for the formation of its 3-oxoalkan-1-one acetals. The initial acylketene acetals are prepared via double oxa-Michael addition of DHN to 1-bromo-1-propyn-3-ones. Carbonucleophiles, including organocopper reagents and active methylene compounds, and heteroatom nucleophiles were introduced under basic conditions. This method is applied for synthesizing spiropreussione A; the proposed structure does not correspond to that of the authentic natural product.