iodine; ((n-Bu)4N)2S2O8 in water; acetonitrile T=50°C; 0.5 h;

1: 80 percent / sodium borohydride / tetrahydrofuran / 55 °C / 2.) methanol 45 min and 1h 2: acetic acid; H2O / 4 h / 50 °C 3: pyridine / Ambient temperature 4: 86 percent / 1.) sodium hydride / dimethylformamide / 1.) 0 deg C 30 min; 2.) 0 deg C 30 min; 3.) room temperature overnight 5: 90 percent / acetic acid; H2O / 1.5 h / 80 °C View Scheme

With  tetrakis(triphenylphosphine) palladium(0) in  1,4-dioxane 0.25 h;  Heating;   

With  sodium tetrahydroborate in  tetrahydrofuran; methanol T=55°C; 2 h;   

Multi-step reaction with 3 steps 1: 80 percent / sodium borohydride / tetrahydrofuran / 55 °C / 2.) methanol 45 min and 1h2: acetic acid; H2O / 4 h / 50 °C3: pyridine / Ambient temperature  

Multi-step reaction with 4 steps 1: 80 percent / sodium borohydride / tetrahydrofuran / 55 °C / 2.) methanol 45 min and 1h2: acetic acid; H2O / 4 h / 50 °C3: pyridine / Ambient temperature4: 86 percent / 1.) sodium hydride / dimethylformamide / 1.) 0 deg C 30 min; 2.) 0 deg C 30 min; 3.) room temperature overnight