Iodine- or Iodine Monobromide-Catalyzed Alkoxy–Alkoxy Exchange Reactions of Alkylalkoxysilanes: Formation of the Catalyst–Alkoxysilane Complexes and the Reaction Mechanism

Abstract

Abstract The formation of charge-transfer complexes of iodine and of iodine monobromide with alcohols and alkoxysilanes has been established spectroscopically, and the formation constants of iodine–ethoxytriethylsilane and iodine–diethoxydimethylsilane complexes has been determined as 0.55±0.01 and 0.61±0.02, respectively. On the basis of these observations and the kinetic information recently reported, the previously proposed mechanism for the iodine or iodine monobromide catalyzed alkoxy–alkoxy exchange reactions of alkoxysilanes is discussed afresh. It has been confirmed that a mechanism involving a four-centered transition state containing a CT-complex is most favorable.