Catalytic oxidations of alcohols - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 141

is a solid) and the product ketone is easily recovered by phase separation.
The catalyst is stable and remains in the aqueous phase which can be
recycled to the next batch.
A wide range of alcohols were oxidized with TOFs ranging from 10 to
100, depending on the solubility of the alcohol in water (since the reaction
occurs in the aqueous phase the alcohol must be at least sparingly soluble in
water). Thus, in a series of straight-chain secondary alcohols the TOFs
decreased from 100 to 13 on increasing the chain length from 1-pentanol to
1-nonanol.
Representative examples of secondary alcohols that were smoothly
oxidized using this system are collected in Table 7. The corresponding
ketones were obtained in >99% selectivity in virtually all cases.
Primary via

further oxidation of the aldehyde intermediate, e.g. 1-hexanol afforded 1-
hexanoic acid in 95% yield. It is important to note, however, that this was
achieved without the requirement of one equivalent of base to neutralize the
carboxylic acid product (which is the case with supported noble metal
catalysts 4 ). In contrast, when 1m% TEMPO (4 equivalents per Pd) was
added the aldehyde was obtained in high yield, e.g. 1-hexanol afforded 1-
hexanal in 97% yield. Some representative examples of primary alcohol
oxidations using this system are shown in Table 8.

alcohols afforded the corresponding carboxylic acids