1: aq. K2OsO4, (DHQD)2PYR, K3Fe(CN)6, K2CO3 / 2-methyl-propan-2-ol / 24 h / 0 °C 2: 1.) pyridinium p-toluenesulfonate, trimethyl orthoacetate, 2.) acetyl bromide, 3.) potassium carbonate View Scheme

orthoacetic acid trimethyl ester; acetyl-bromide; pyridinium p-toluenesulfonate; potassium carbonate Multistep reaction;