1.1: di-isopropyl ether / 6 h / 20 - 75 °C 2.1: hydrogenchloride / water; tert-butyl methyl ether / 0.5 h / 20 - 25 °C 3.1: thionyl chloride / toluene / 3 h / 75 - 80 °C 4.1: sodium carbonate / toluene; water / 1 h / 0 - 5 °C 5.1: dimethylsulfide borane complex / tetrahydrofuran / 3 h / 20 - 80 °C / Inert atmosphere 5.2: 0.5 h / 0 - 5 °C View Scheme

1.1: thionyl chloride / toluene / 3 h / 75 - 80 °C 2.1: sodium carbonate / toluene; water / 1 h / 0 - 5 °C 3.1: dimethylsulfide borane complex / tetrahydrofuran / 3 h / 20 - 80 °C / Inert atmosphere 3.2: 0.5 h / 0 - 5 °C 4.1: hydrogen bromide / water / 3 h / 90 - 100 °C 5.1: (2S,3S)-(+)-di-O-benzoyl tartaric acid / isobutyl methylketone; methanol / 25 °C 5.2: pH 8 View Scheme