Carbonyl compounds adjacent silyl group

Acylsilanes are a class of compounds in which a silyl group is directly bound to the carbonyl carbon, and they have received considerable research interest from the point of view of both physical organic and synthetic organic chemistry [15]. Acylsilanes have a structure quite similar to the structure of a-silyl-substituted ethers a silyl group is attached to the carbon adjacent to the oxygen atom, although the nature of the C-O bond is different. Therefore, one can expect /1-silicon effects in the electron-transfer reactions of acylsilanes. 

Studies on the electrochemical oxidation of silyl-substituted ethers have uncovered a rich variety of synthetic application in recent years. Since acetals, the products of the anodic oxidation in the presence of alcohols, are readily hydrolyzed to carbonyl compounds, silyl-substituted ethers can be utilized as efficient precursors of carbonyl compounds. If we consider the synthetic application of the electrooxidation of silyl-substituted ethers, the first question which must be solved is how we synthesize ethers having a silyl group at the carbon adjacent to the oxygen. We can consider either the formation of the C-C bond (Scheme 15a) or the formation of the C-O bond (Scheme 15b). The formation of the C Si bond is also effective, but this method does not seem to be useful from a view point of organic synthesis because the required starting materials are carbonyl compounds. 

Bioactive compounds that contain the difluoromethylene group adjacent to the carbonyl functionality have been the subject of increased research efforts in recent yearsf 59). The most widely utilized methods that have been employed to introduce this group into organic molecules have been (a) Reformatsky reaction of halodifluoroacetates (60-66) (b) elaboration of difluoroketene silyl acetals (67-69) (c) metal catalyzed addition of 3-bromo-3,3-difluoropropene to aldehydes and ketones (70) and (d) alkylation of CuCF2COOR(77). The modest yields associated with these methods prompted us to explore alternative methodology for the preparation of this useful building block. 

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