sodium acetate; bis(benzoyloxy)borane in chloroform T=0°C; 0.5 h;

dimethylsulfide; methyllithium; oxygen; ozone 1.) benzene, ice bath, 4 h; 2.) CH2Cl2, -78 deg C; 3.) CH2Cl2, room temperature overnight; Yield given. Multistep reaction;