Total synthesis of Oboflavanone B

Oboflavanone B, a revision of Oboflavanone A, has unique structure. Intrigued by its key 2,8-dioxabicyclo(3.3.1)nonane structure and chromanone structure, this paper discussed and reported a proposal towards the synthesis of this product. This work provides a theoretically feasible retrosynthesis, which utilized coupling reactions to connect the two main parts of the natural product. The key strategy of these syntheses involves Heck reactions, Fries rearrangement and addition reactions. To ensure the chiral of the target product, the chiral of the reactant was restricted in this work. The synthesis went through a total 12 steps process, containing 4 steps on protecting and deprotecting reactions. All the substrates given in each step are available in this strategy.