Transformation of carboxylic acid salts to aldehydes by stepwise reductionwith borane and oxidation with pyridinium chlorochromate

The stepwise reduction-oxidation method has been successfully applied to co nversion of carboxylic acid salts to the corresponding aldehydes. Thus, bot h sodium and lithium salts of carboxylic acid were readily converted to ald ehydes in essentially quantitative yields by stepwise treatment with borane and dimethyl sulfate, and followed by oxidation with PCC. Alternatively, t he treatment of acid salts with two equivalents of borane in THF, and follo wed by the oxidation also provided the same results.