MacDonald-Fischer degradation

What is MacDonald-Fischer degradation?

In 1952, MacDonald and Fischer first reported a reaction that involves the degradation of hexoses into pentoses. This process includes several steps such as the formation of dithioacetal, oxidation to unsaturated disulfone using perphthalic acid, hydrazine treatment, and splitting of the corresponding hydrazone with benzaldehyde. The complete process is commonly referred to as the MacDonald-Fischer degradation.

MacDonald-Fischer degradation - general reaction scheme
MacDonald-Fischer degradation

Furthermore, the unsaturated disulfone, when dissolved in aqueous ammonia or methanol saturated with ammonia, leads to the resolution of 2-deoxy-2-amino sugar. This reaction, when combined with mass spectrometry, has been used to examine the structure and stereochemistry of carbohydrates.


The Degradation of Sugars by Means of their Disulfones1
D. L. MacDonald and Hermann O. L. Fischer
Journal of the American Chemical Society 1952 74 (8), 2087-2090
DOI: 10.1021/ja01128a071