Alcohols, secondary, oxidation with trichloroacetaldehyde

Several new procedures for the selective oxidation of secondary alcohols in the presence of primary alcohols have appeared. Distannoxane-bromine, a neutral reagent, efficiently oxidizes secondary or benzylic alcohols to ketones in the presence of primary alochols.62 Trialkyltin alkoxides and bromine oxidize both primary and secondary alcohols.63 Woelm W-200, neutral, dehydrated alumina oxidizes secondary alcohols to ketones in the presence of primary alcohols with trichloroacetaldehyde as the hydride acceptor.6 The reverse reduction process had previously been reported. Oxidation of triphenylmethyl ethers of primary, secondary diols with triphenyl carbenium salts proceeds only at the secondary positions.65... 

Oxidation and Reduction.—A number of selective oxidation procedures have been reported. Trichloroacetaldehyde on dehydrated chromatographic alumina converts the diol (15) into the 3/3-hydroxy-17-ketone (68%)." Primary alcohols are reported to be less readily oxidized than secondary alcohols by this reagent. Similarly, bromine or chlorine with HMPA oxidizes secondary alcohols more readily than primary alcohols. Thus the diol (16) was converted into the ketol (17)... 

The selective oxidation of secondary alcohols which contain either a sulfide or selenide is also possible using either selenium-based oxidizing agents (equations 39 and 40), or with a modified Oppe-nauer system involving trichloroacetaldehyde (equation 41). ... 

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