Selective trifluoromethanesulfonations, alcohols

The formylmethyl complex 21 also serves as a source of free acetaldehyde, and one equivalent of trifluoromethanesulfonic acid in CH2CI2 releases it from 21 within one hour at room temperature. Acetaldehyde was identified by its 2,4-dinitrophenylhydrazone (isolated in 42% yield), and was determined directly (48%) by quantitative analysis of its IR v 1716 cm"l absorption. The protonation of 21 presumably generates a n2-vinyl alcohol compound 19 (R=H) [IR observable v 1983 cm" ], which then dissociates acetaldehyde. We have overall converted selectively two carbonyls on CpFe(CO)3+ (1) to acetaldehyde. 

Catalytic oxidation of beech organosolv lignin in ionic liquid (l-ethyl-3-methylimidazolium trifluoromethanesulfonate) at 100°C and 8 MPa air in the presence of 20% Mn(N03)2 formed DMBQ 25 in 11.5% isolated yield and 21% selectivity. The amount of 25 formed under these conditions depended on the catalyst level. At 2% catalyst, the product slate shifted to a mixture of syringaldehyde, syringyl alcohol, and vanillin, with only trace amounts of DMBQ observed. The authors propose that DMBQ results from syringaldehyde oxidation [100]. 

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