Hypervalent iodine reagents have been employed for the conversion of tyrosine derivatives 4a-d, 5 into 3-substituted 1-oxaspiro[4.5]deca-6,9-diene-2,8-diones 3a-d, 6, which are precursors for aranorosin synthesis. Model studies have been carried out to investigate cyclohexadienone epoxidation: dimethyldioxirane has been found to produce mono- 7, 8 and diepoxides 9,10 in good overall yield.