2: tetrabutylammonium fluoride,THF / pyridine / 24 h 3: 1.) NaIO4 2.) DBU / 1.) 6 h 2.) 18 h. Variant: NH4OH, 50 deg C, 2 h View Scheme

2: tetrabutylammonium fluoride,THF / pyridine / 24 h View Scheme