Ring contraction reactions of carbocyclic compounds can be carried out by acids, bases, oxidizers and photochemically. The ring contraction reactions are divided into five main groups: (i) acid-induced ring contractions; (ii) base-induced ring contractions; (iii) oxidative rearrangements; (iv) photochemical rearrangements; and (v) Wolff rearrangements. [²] Since the transformation of carbocyclic compounds, particularly of quinones into different ...
[Baxter, Paul N. W.; Connor, Joseph A.; Wallis, John D.; Povey, David C.; Powell, Anne K. Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999), 1992 , # 13 p. 1601 - 1606]
![5H-Cyclopenta[2,1-b:3,4-b']dipyridin-5-one Structure](https://image.chemsrc.com/caspic/241/50890-67-0.png)