No abstract

In 1948, Newman and Smith (1) reported the preparation of ketones in high yields by the interaction of Grignard reagents and acid anhydrides at -70". Four years later, Hauser and Hance (2) described the preparation of trimethylsilylacetone and of 1-trimethylsilyl-1-phenylacetone by the interaction of trimethylsilylmethylmagnesium bromide and of trimethylsilylphenylmethylmagnesium bromide, respectively, with acetic anhydride :In this work, use was made of the method of Gruttner and Cauer (3, 4) in the preparation of several secondary sila-alcohols. These alcohols have now been oxidized by the Oppenauer method (5-7) 11.In this manner there have been prepared p-triethylsilylphenyl methyl ketone, p-triethylsilylphenyl ethyl ketone, p-triethylsilylphenyl n-propyl ketone, p-triethylsilylphenyl isopropyl ketone and p-triethylsilylphenyl phenyl ketone in respective percentage yields of 41.8, 22.8, 33.3, 48.0, and 59.5.p-Trimethylsilylphenylphenylcarbinol was oxidized to the corresponding ketone by the Oppenauer method, yield 22.8 %.In the second method of approach to the problem of ketone formation, p-triethylsilylphenylmagnesium bromide was added to acetic anhydride. p-Triethylsilylphenyl methyl ketone was obtained in 38% yield. Similarly, using the proper acid anhydrides, p-triethylsilylphenyl ethyl ketone, p-triethylsilylphenyl n-propyl ketone, and p-triethylsilylphenyl phenyl ketone were prepared in respective percentage yields of 19.0, 30.0, and 24.0. Corresponding ketones were prepared from the interaction of p-trimethylsilylphenylmagnesium bromide and acetic anhydride (39.0 % yield), propionic anhydride (44.0 %), n-butyric anhydride (31.0 %), and benzoic anhydride (33.0 %). EXPERIMENTAL PARTp-Trimethylsilylphenyl methyl ketone. I n a SOO-cc., three-necked flask equipped with a mercury-sealed stirrer, dropping-funnel, and reflux condenser, 0.15 mole of p-trimethylsilylphenylmagnesium bromide was added slowly, in 50 cc. of dry ethyl ether, to 14 cc. (0.15 mole) of acetic anhydride in 130 cc. of dry ethyl ether, at -70°, with stirring.