β-Cleavage of Bis(homoallylic) Potassium Alkoxides. Synthesis of γ-damascone

Starting from the γ-lactone cis- 1 , two new syntheses of γ-damascone ((E)- 4 ) are described. In both syntheses, the key step involves the β-cleavage of a bis(homoallylic) potassium alkoxide, viz. the transformation of 3a to 20 and (E/Z)- 4 , and the conversion of 21a to 23 and (E/Z)- 24 .