To a solution of 7-methoxy-4-methyl-1,2-dihydronaphthalene (100 mg, 0.57 mmol) in acetone (2.5 mL) were added ethyl acetate (0.5 mL), water (0.5 mL) and solid NaHCO₃ (145 mg, 1.72 mmol) and the reaction mixture was stirred for 10 min. To this was added solid Oxone (706 mg, 1.15 mmol) and contents were stirred at room temperature for 8 h. After completion of the reaction, the excess acetone evaporated under reduced pressure and remaining reaction mixture portioned between water and ethyl acetate (20 mL each). The organic layer was separated and the aqueous layer extracted with ethyl acetate (2 x 20 mL). Combined organic layer was dried (Na₂SO₄) and concentrated under reduced pressure. The crude product was purified by silica gel column (ethyl acetate and pet ether as eluent) to afford the 7-Methoxy-2,2,9b-trimethyl-3a,4,5,9b-tetrahydronaphtho[1,2-d][1,3]dioxole (101 mg, 71%) as colourless liquid.

Phatake, R. S.; Ramana, C. V. Tetrahedron Lett. 2015, 56, 2183-2186. (http://dx.doi.org/10.1016/j.tetlet.2015.03.022)