1: 1.) Pd(OAc)2, 2.) Na2CO3 / 1.) acetonitrile, 2 h, 2.) acetonitrile, 21 h 2: 86 percent / tetrabutylammonium fluoride, AcOH / tetrahydrofuran / 0.5 h / -78 °C 3: 27 percent / aq.NaBH4 / methanol / 0.5 h / 0 °C 4: 94 percent / tetrabutylammonium fluoride / tetrahydrofuran / 0.5 h View Scheme