Reagents and Conditions. a) Dess-Martin periodinane, an. CH2Cl2, 80%; b) Tetraisopropyl methylenediphosphonate, NaH, an. THF, 83%; c) 2 M NH3 in i-PrOH, 70 °C, 80%; d) 10% Pd/C, H2 (3 bar), MeOH:2M aq. NaOH (1:1, v/v), 79%; e) Iodotrimethylsilane, an. CH2Cl2, 47% for 10 and 28% for 7.