Organocatalytic Regioselective Chlorosilylation of Oxirane Derivatives: Mild and Effective Insertion of Bulky Silyl Chloride by Using 4-Methoxypyridine N-Oxide

The highly regioselective organocatalytic chlorosilylation of oxirane derivatives using bulky silyl reagents such as (tert-butyl)diphenylsilyl chloride (TBDPSCl) or triphenylsilyl chloride (Ph3SiCl) was developed. The reaction was effectively catalyzed with 4-methoxypyridine N-oxide in the presence of sodium sulfate (Na2SO4). Several silylated halohydrins were obtained with complete regioselectivity and the reaction was applied to the synthesis of carvedilol.