1: 95 percent / MeONa / diethyl ether / 1.) -15 deg C, 90 min, 2.) 4 deg C, overnight 2: 43 percent / t-BuOK, dicyclohexano<18>crown-6 / tetrahydrofuran / 1.) -50 deg C, 45 min, 2.) slowly to r.t. View Scheme

methanesulfonamide; AD-mix-β in water; tert-butyl alcohol T=0°C; Yield given;

AD-mix-α; methanesulfonamide in water; tert-butyl alcohol T=0°C; Yield given;