phosphorous acid trimethyl ester in methanol T=22°C; 24 h;

1: 1.) n-BuLi / 1.) THF, hexane, 0 deg C, 30 min, 2.) from 0 to room temp. 2: 93 percent / m-chloroperbenzoic acid / CH2Cl2 / 1 h / -78 °C 3: 90 percent / trimethyl phosphite / methanol / 24 h / 22 °C View Scheme

1: 93 percent / m-chloroperbenzoic acid / CH2Cl2 / 1 h / -78 °C 2: 90 percent / trimethyl phosphite / methanol / 24 h / 22 °C View Scheme

1: air / hexane; tetrahydrofuran 2: water ice / hexane; tetrahydrofuran View Scheme

acetyl-bromide; sodium hydride 1.) THF, 45 min, 2.) -5 deg C, 3 d; Multistep reaction;