1: 81 percent / n-Bu3SnH; AIBN / toluene / 4 h / Heating 2: 94 percent / TBAF / tetrahydrofuran / 2 h / 20 °C View Scheme

2,2'-azo-bisisobutyronitrile; tri-n-butyl-tin hydride in toluene Barton reduction; 4 h; Heating;