1: 98 percent / NaBH4, BF3*OEt2 / bis-(2-methoxy-ethyl) ether 2: 9.8 percent / decahydronaphthalene / 2.5 h / 190 °C 3: 62 percent / DIBAH / hexane; tetrahydrofuran / 0.75 h / -15 °C 4: 85 percent / 10percent KOH / ethanol; H2O / 16 h / 70 °C 5: 85 percent / Corey oxidation View Scheme