Reactions of Organo(trifluoroacetoxy)silanes with Alcohols and Epoxides

Abstract

Trimethyl(trifluoroacetoxy)silane and diphenylbis (trifluoroacetoxy) silane reacted with alcohols at room temperature, to give the corresponding alkyl trifluoroacetates in good yields. With polyols such as ethylene glycol and glycerol, the diester and the triester were formed. The gas-chromatographic investigation revealed that the reaction proceeded via following three steps:
R3SiOCOCF3 ROH R3SiOR CF8CO₂1-1 R3SiOR CF3CO₂H
R3SiOH CF3CO₂R R3SiOH 1/2 (R3SiOSiR3 + H₂0)
The reaction of trimethyl (trifluoroacetoxy) silane with epoxy compounds also proceeded smoothly at room temperature. In this case, the ring-opening of the epoxide, followed by an insertion between Si and OCOCF3 occurred. Thus, with propylene oxide it gave a mixture of two isomers, CF3CO₂CH(Me)CH₂0SiMe8 and CF8CO₂CH₂CH (Me)0SiMe, , and with epichlorohydrin, it gave almost pure CF3CO₂CH₂CH(Cl-12Cl)0SiMe3.