acetic acid Yield given. Multistep reaction;

Multi-step reaction with 8 steps 2: Pd(MeCN)2Cl2 / tetrahydrofuran / 2 h / Ambient temperature3: NaBH4 4: protected as tetrahydropyranyl ether5: 84 percent / TBAF6: 98 percent / deacylation7: 73 percent / triphenylphosphine, diethylazodicarboxylate / tetrahydrofuran / 0.08 h / Ambient temperature8: diisobutyl aluminum hydride  

Multi-step reaction with 6 steps 1: NaBH4 2: protected as tetrahydropyranyl ether3: 84 percent / TBAF4: 98 percent / deacylation5: 73 percent / triphenylphosphine, diethylazodicarboxylate / tetrahydrofuran / 0.08 h / Ambient temperature6: diisobutyl aluminum hydride  

Multi-step reaction with 7 steps 1: Pd(MeCN)2Cl2 / tetrahydrofuran / 2 h / Ambient temperature2: NaBH4 3: protected as tetrahydropyranyl ether4: 84 percent / TBAF5: 98 percent / deacylation6: 73 percent / triphenylphosphine, diethylazodicarboxylate / tetrahydrofuran / 0.08 h / Ambient temperature7: diisobutyl aluminum hydride  

Multi-step reaction with 5 steps 1: protected as tetrahydropyranyl ether2: 84 percent / TBAF3: 98 percent / deacylation4: 73 percent / triphenylphosphine, diethylazodicarboxylate / tetrahydrofuran / 0.08 h / Ambient temperature5: diisobutyl aluminum hydride