Remodeling of the Natural Product Fumagillol Employing a Reaction Discovery Approach

In search for new biologically active molecules, diversity-oriented synthetic (DOS) strategies break through the limitation of traditional library synthesis by sampling new chemical space. Many natural products can be regarded as intriguing starting points for DOS, wherein stereochemically rich core structures may be reorganized into chemotypes which are distinctly different from the parent structure. Ideally such transformations should be general and involve few steps in order to be suited for library applications. With this objective in mind, the highly oxygenated natural product fumagillol has been successfully remodeled in several ways utilizing a reaction discovery-based approach. In reactions with amines, excellent regiocontrol in a bis-epoxide opening/cyclization sequence can be obtained by size-dependent interaction of an appropriate catalyst with the parent molecule, forming either perhydroisoindole or perhydroisoquinoline products. Perhydroisoindoles can be further remodeled by cascade processes to afford either morpholinone or bridged 4,1-benzoxazepine-containing structures.