Scheme 3. Previous proposals for the pathway from emodin 1 to monodictyphenone 12. Please see Section 3.1 and Scheme 5B for the most likely pathway based on recent work by Lu and colleagues.75 (A) Original monodictyphenone 12 pathway proposed by Chiang et al.33 (B) Proposal by Simpson in 2012,65 which reconciled all available evidence at the time, including the identification of chrysophanol 2 as a likely intermediate.
