Marschalk reaction explained

The Marschalk reaction in chemistry is the sodium dithionite promoted reaction of a phenolic anthraquinone with an aldehyde to yield a substituted phenolic anthraquinone after the addition of acid.

The mechanism can be found in the book Named Reactions in Organic Chemistry,^[1] and its more intuitive version is provided below:

One of the first applications of this reaction was reported in 1985.^[2]

Notes and References

1. Book: Mundy, Bradford P. . Ellerd, Michael G. . Favaloro, Frank G. Jr. . amp . Name Reactions and Reagents in Organic Synthesis . 2005 . John Wiley & Sons . 978-0-471-73986-9 . 411–.
2. 10.1002/jlac.198519850704. Reaction of Anthrahydroquinones with α,β-Unsaturated Carbonyl Compounds. 1985. Krohn. Karsten. Miehe. Frank. Liebigs Annalen der Chemie. 1985. 7. 1329.