1: 1) (COCl)2, DMSO, 2) Et3N 2: MCPBA / CH2Cl2 / 3 h / phosphate buffer (pH 7) 3: LiAlH4 / diethyl ether / 1 h / 0 °C 4: 1) (COCl)2, DMSO, 2) Et3N View Scheme

With  sodium tetrahydroborate in  methanol T=0°C; 0.25 h;